fix(demography): color scale typo for "Net migration rate" (#37)

A `1` should've been a `-1`.

scripts/demography-explorer/metrics.csv

@@ -145,7 +145,7 @@ Population growth rate,Population growth rate,growth_rate__${sex__slug}__${age_g
 ${sex__title_prefix} life expectancy at birth,Life expectancy,life_expectancy__${sex__slug}__${age_group__csv_slug}__${projection__slug},life_expectancy__${sex__slug}__full__${projection__slug},${projection__subtitle},LineChart,Shown is the ‘period life expectancy’ at birth. This is the average number of years a newborn would live if age-specific mortality rates in the current year were to stay the same throughout its life.,0,true,,,all female male,at_birth,records medium,Numeric,years,years,30;40;50;60;70;80;90;1,YlGn,
 ${sex__title_prefix} life expectancy ${age_group__title_suffix},Life expectancy,life_expectancy__${sex__slug}__${age_group__csv_slug}__${projection__slug},life_expectancy__${sex__slug}__full__${projection__slug},"Life expectancy for individuals who have reached age ${age_group__csv_slug}. Estimates are expressed as the expected age at death, not as years left to live. ${projection__subtitle}",LineChart,,0,true,,,all female male,aged_15 aged_65 aged_80,records medium,Numeric,years,years,,YlGn,
 Net migration,Net migration,net_migration__${sex__slug}__${age_group__slug}__${projection__slug},net_migration__${sex__slug}__full__${projection__slug},The total number of immigrants (people moving into a given country) minus the number of emigrants (people moving out of the country). ${projection__subtitle},LineChart,,0,true,,,all,all,records medium,Integer,,migrants,-100000;-50000;-20000;0;20000;50000;100000;250000,RdBu,
-Net migration rate,Net migration rate,net_migration_rate__${sex__slug}__${age_group__slug}__${projection__slug},net_migration_rate__${sex__slug}__full__${projection__slug},"The total number of immigrants (people moving into a given country) minus the number of emigrants (people moving out of the country), per 1,000 people in the population. ${projection__subtitle}",LineChart,,0,true,,,all,all,records medium,Numeric,,"per 1,000 population",-30;-10;-3;1;0;1;3;10;30;31,RdBu,
+Net migration rate,Net migration rate,net_migration_rate__${sex__slug}__${age_group__slug}__${projection__slug},net_migration_rate__${sex__slug}__full__${projection__slug},"The total number of immigrants (people moving into a given country) minus the number of emigrants (people moving out of the country), per 1,000 people in the population. ${projection__subtitle}",LineChart,,0,true,,,all,all,records medium,Numeric,,"per 1,000 population",-30;-10;-3;-1;0;1;3;10;30;31,RdBu,
 Sex ratio,Sex ratio,sex_ratio__none__${age_group__csv_slug}__${projection__slug},sex_ratio__none__full__${projection__slug},​​The number of male population per 100 female population. ${projection__subtitle},LineChart,,,true,,,all,all,records low medium high,Numeric,,males per 100 females,90;95;100;105;110;115;1,Blues,85
 Sex ratio at birth,Sex ratio,sex_ratio__none__${age_group__csv_slug}__${projection__slug},sex_ratio__none__full__${projection__slug},"​​The number of male births per 100 female births. Biological birth ratios are slightly male-biased, with an expected ratio of 105 male births per 100 female births. ${projection__subtitle}",LineChart,,,true,,,all,at_birth,records low medium high,Numeric,,males per 100 females,102;103;104;105;106;107;108;109,Blues,101
 Sex ratio ${age_group__title_suffix},Sex ratio,sex_ratio__none__${age_group__csv_slug}__${projection__slug},sex_ratio__none__full__${projection__slug},"The number of male individuals per 100 female individuals, ${age_group__title_suffix}. ${projection__subtitle}",LineChart,,,true,,,all,5,records low medium high,Numeric,,males per 100 females,100;101;102;103;104;105;106;107;108;1,Blues,99
@@ -163,4 +163,4 @@ Sex ratio ${age_group__title_suffix},Sex ratio,sex_ratio__none__${age_group__csv
 Total ${sex__title_prefix} dependency ratio,Dependency ratio,dependency_ratio_total__${sex__slug}__none__${projection__slug},dependency_ratio_total__${sex__slug}__full__${projection__slug},The ratio of the young ${sex__title_prefix} population (under age 15) and elderly population (aged 65 and over) to the working-age ${sex__title_prefix} population (aged 15 to 64). ${projection__subtitle},LineChart,,0,true,,,all female male,dependency_total,records low medium high,Numeric,%,%,40;50;60;70;80;90;100;1,GnBu,35
 ${sex__title_prefix} youth dependency ratio,Dependency ratio,dependency_ratio_child__${sex__slug}__none__${projection__slug},dependency_ratio_child__${sex__slug}__full__${projection__slug},The ratio of the young ${sex__title_prefix} population (under age 15) to the working-age ${sex__title_prefix} population (aged 15 to 64). ${projection__subtitle},LineChart,,0,true,,,all female male,dependency_child,records low medium high,Numeric,%,%,20;30;40;50;60;70;80;90;100;1,GnBu,19
 ${sex__title_prefix} old-age dependency ratio,Dependency ratio,dependency_ratio_old__${sex__slug}__none__${projection__slug},dependency_ratio_old__${sex__slug}__full__${projection__slug},The ratio of the elderly ${sex__title_prefix} population (aged 65 and over) to the working-age ${sex__title_prefix} population (aged 15 to 64). ${projection__subtitle},LineChart,,0,true,,,all female male,dependency_old,records low medium high,Numeric,%,%,5;10;15;20;25;30;35;40;1,GnBu,0.5
-Median age,Median age,median_age__${sex__slug}__all__${projection__slug},median_age__${sex__slug}__full__${projection__slug},"The median age divides the population into two parts of equal size; that is, there are as many people with ages above the median age as there are with ages below. ${projection__subtitle}",LineChart,,0,true,,,all,none,records low medium high,Numeric,,years,15;20;25;30;35;40;45;1,GnBu,14.9
+Median age,Median age,median_age__${sex__slug}__all__${projection__slug},median_age__${sex__slug}__full__${projection__slug},"The median age divides the population into two parts of equal size; that is, there are as many people with ages above the median age as there are with ages below. ${projection__subtitle}",LineChart,,0,true,,,all,none,records low medium high,Numeric,,years,15;20;25;30;35;40;45;1,GnBu,14.9