github/workflow: fix macos

For macos-latest runner on Github using macos14 on arm there is only Python
>= 3.11 available.

We have to install pytest and dmgbuild manually

.github/workflows/macos.yml

@@ -9,14 +9,18 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v3
-      - name: Set up Python 3.8
+      - name: Set up Python 3.11
         uses: actions/setup-python@v4
         with:
-          python-version: 3.8
+          python-version: 3.11
       - name: Install deps
         run: ./tools/macos-setup-brew.sh --install-optional --install-doc-deps --install-dmg-deps --install-test-deps
         env:
           HOMEBREW_NO_AUTO_UPDATE: 1
+      - name: Install pytest
+        run: pip3 install pytest pytest-xdist
+      - name: Install dmgbuild
+        run: pip3 install dmgbuild
       - name: Mkdir
         run: mkdir build
       - name: Cmake