ign -> gz Environment Variable Migration : gz-rendering

[methylDragon]

See: gazebo-tooling/release-tools#734

Actually no environment variables need to be migrated (though how it's been implemented means there isn't really a way to emit warnings...)

They were implemented like so in the namespace migration:

  const char *env = std::getenv("GZ_RENDERING_RESOURCE_PATH");
  env = (env) ? env : std::getenv("IGN_RENDERING_RESOURCE_PATH");

[codecov]

Codecov Report

Merging #639 (3892ad9) into main (bc2d7ba) will decrease coverage by 0.02%.
The diff coverage is 42.85%.

❗ Current head 3892ad9 differs from pull request most recent head 5192651. Consider uploading reports for the commit 5192651 to get more accurate results

@@            Coverage Diff             @@
##             main     #639      +/-   ##
==========================================
- Coverage   53.61%   53.59%   -0.03%     
==========================================
  Files         214      214              
  Lines       21369    21397      +28     
==========================================
+ Hits        11457    11467      +10     
- Misses       9912     9930      +18     

Impacted Files	Coverage Δ
ogre/src/OgreDepthCamera.cc	0.00% <0.00%> (ø)
ogre/src/OgreMaterial.cc	40.30% <0.00%> (-0.50%)	⬇️
ogre/src/OgreRTShaderSystem.cc	43.84% <60.00%> (+0.09%)	⬆️
ogre/src/OgreRenderEngine.cc	73.45% <60.00%> (-0.29%)	⬇️
ogre2/src/Ogre2RenderEngine.cc	78.32% <60.00%> (-0.50%)	⬇️
src/base/BaseScene.cc	72.54% <60.00%> (-0.13%)	⬇️

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[chapulina]

I just noticed that we're not printing warnings when the user uses the IGN_ vars. Would you mind adding warnings as part of this PR?

[methylDragon]

I just noticed that we're not printing warnings when the user uses the IGN_ vars. Would you mind adding warnings as part of this PR?

5192651 !

[chapulina]

Thanks! LGTM