[cppgraphqlgen] Update to v2.0.0#5308

Merged

ras0219-msft merged 3 commits intomicrosoft:masterfrom

wravery:cppgraphqlgen

Feb 9, 2019

Commits on Feb 6, 2019

Commits on Feb 7, 2019

[cppgraphqlgen] Pick up bug fix v2.0.2
wravery
committed