Migrate Python packaging to pyproject.toml (#2782)

This changelist migrates the MaterialX Python packaging configuration from the legacy `setup.py` script to the modern `pyproject.toml` standard, as defined in PEP 517 and PEP 621.

Author: jstone-lucasfilm

python/CMakeLists.txt

@@ -12,7 +12,7 @@ if(SKBUILD)
 endif()
 
 if(MATERIALX_INSTALL_PYTHON AND PYTHON_EXECUTABLE AND NOT SKBUILD)
-  set(SETUP_PY "${CMAKE_INSTALL_PREFIX}/python/setup.py")
-  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/setup.py.in" "${SETUP_PY}")
+  set(PYPROJECT_TOML "${CMAKE_INSTALL_PREFIX}/python/pyproject.toml")
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/pyproject.toml.in" "${PYPROJECT_TOML}")
   install(CODE "execute_process(COMMAND ${PYTHON_EXECUTABLE} -m pip install . WORKING_DIRECTORY ${CMAKE_INSTALL_PREFIX}/python)")
 endif()

python/MaterialX/MANIFEST.in

@@ -0,0 +1,13 @@
+[build-system]
+requires = ["setuptools"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "MaterialX"
+version = "${MATERIALX_MAJOR_VERSION}.${MATERIALX_MINOR_VERSION}.${MATERIALX_BUILD_VERSION}"
+
+[tool.setuptools]
+packages = ["MaterialX"]
+
+[tool.setuptools.package-data]
+MaterialX = ["**/*"]