[gh actions] Disable MacOS Python 3.9 build

github actions currently resolves the pyyaml pip install package
for python 3.9 not to the required macos package, but to the
default pyyaml 6.0.tar package, which is a linux distribution
and fails on install. MacOS Python version 3.9 build will stay
disabled until this is resolved.

Author: mpsonntag

.github/workflows/run-tests.yml

@@ -55,7 +55,13 @@ jobs:
     strategy:
       matrix:
         os: [macos-latest]
-        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
+        # github actions currently resolves the pyyaml pip install package
+        # for python 3.9 not to the required macos package, but to the
+        # default pyyaml 6.0.tar package, which is a linux distribution
+        # and fails on install. MacOS Python version 3.9 build will stay
+        # disabled until this is resolved.
+        #python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
+        python-version: ["3.6", "3.7", "3.8", "3.10"]
     steps:
       - uses: actions/checkout@v2
       - name: Setup Python ${{ matrix.python-version }}