Revert "On macOS install official Python"

This reverts commit a99e6916cfd145dcbc9ecac0d5323a6f86c4d867.

.github/workflows/qt5_6.yml

@@ -120,13 +120,10 @@ jobs:
             brew install qt@${{ inputs.qt_version }} vulkan-headers ninja libftdi || true
           echo '::endgroup::'
 
-          echo '::group::Install official Python'
-            # We need the official Python, because the GA ones only support newer macOS versions
-            export PYTHON_VERSION=$(python3 --version | cut -d' ' -f2 | cut -d'.' -f1,2)
-            curl https://www.python.org/ftp/python/${PYTHON_VERSION}/python-${PYTHON_VERSION}-macos11.pkg -o "python.pkg"
-            sudo installer -pkg python.pkg -target /
-            python3 --version
-          echo '::endgroup::'
+      - name: Temporarily downgrade CMake to 3.28.3 # Please remove if GitHub has updated Cmake (greater than 3.30.0)
+        uses: jwlawson/actions-setup-cmake@v2
+        with:
+          cmake-version: '3.28.3'
 
       - name: 👷 Build
         shell: bash