imporove release workflow ( installing plugins is now easier than before)

[KirisameMarisa]

• Unity
  • Created .unitypackage
    • Added unity project for the above
    • Included flatbuffers.dll
• Godot
  • Multi-platform support
• UnrealEngine
  • Included flatbuffer .h/.lib in UnrealEngine

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (8cac813) 30.29% compared to head (7c2cd12) 30.29%.
Report is 1 commits behind head on master.

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #89   +/-   ##
=======================================
  Coverage   30.29%   30.29%           
=======================================
  Files          99       99           
  Lines        2862     2862           
  Branches      388      388           
=======================================
  Hits          867      867           
  Misses       1940     1940           
  Partials       55       55           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.