[imgui] Update to 1.77#12155

Merged

ras0219-msft merged 4 commits intomicrosoft:masterfrom

RT2Code:imgui

Jul 1, 2020

Commits on Jun 13, 2020

[imgui] Add Freetype feature
RT2Code
authored

Commits on Jun 29, 2020

Commits on Jul 1, 2020

[imgui] Fix INSTALL_INTERFACE path case
RT2Code
authored