message: Update deprecated MacOS environment
  This changelist updates a deprecated MacOS environment in our build matrix for GitHub Actions, switching from macos-10.15 to macos-11.
diff: @@ -74,12 +74,12 @@ jobs:
  cmake_config: -DMATERIALX_DYNAMIC_ANALYSIS=ON
  dynamic_analysis: ON
  - - name: MacOS_Xcode_10_Python27
  - os: macos-10.15
  + - name: MacOS_Xcode_11_Python37
  + os: macos-11
  compiler: xcode
  - compiler_version: "10.3"
  - python: 2.7
  - cmake_config: -DMATERIALX_PYTHON_VERSION=2 -DMATERIALX_BUILD_SHARED_LIBS=ON
  + compiler_version: "11.7"
  + cmake_config: -DMATERIALX_BUILD_SHARED_LIBS=ON
  + python: 3.7
  - name: MacOS_Xcode_12_Python37
  os: macos-11
  