fix(ci): fix heroku, deploy only demo/dist

[IlyaSurmay]

PR Checklist

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• read and followed the CONTRIBUTING.md guide.
• built and tested the changes locally.

[codecov]

Codecov Report

Merging #3441 into development will increase coverage by 0.42%.
The diff coverage is n/a.

@@              Coverage Diff               @@
##           development   #3441      +/-   ##
==============================================
+ Coverage        64.98%   65.4%   +0.42%     
==============================================
  Files              210     210              
  Lines             5695    5649      -46     
  Branches          1002     890     -112     
==============================================
- Hits              3701    3695       -6     
- Misses            1729    1757      +28     
+ Partials           265     197      -68

Impacted Files	Coverage Δ
src/bs-moment/index.ts	100% <0%> (ø)	⬆️
src/sortable/index.ts	100% <0%> (ø)	⬆️
src/dropdown/bs-dropdown-container.component.ts	25.92% <0%> (ø)	⬆️
...themes/bs/bs-datepicker-day-decorator.directive.ts	100% <0%> (ø)	⬆️
...c/datepicker/bs-daterangepicker-input.directive.ts	26.15% <0%> (ø)	⬆️
demo/src/app/app.component.ts	34.28% <0%> (ø)	⬆️
src/index.ts	100% <0%> (ø)	⬆️
src/datepicker/reducer/bs-datepicker.effects.ts	17.75% <0%> (ø)	⬆️
src/datepicker/bs-datepicker-input.directive.ts	28.33% <0%> (ø)	⬆️
...ker/themes/bs/bs-datepicker-container.component.ts	38.7% <0%> (ø)	⬆️
... and 29 more

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