CI: use the right Python in the Homebrew jobs

Update the path added to the $PATH to reflect the installation path
change in recent Homebrew releases.

Author: dnicolodi

.github/workflows/tests.yml

@@ -280,15 +280,11 @@ jobs:
       - name: Install Homebrew Python
         run: |
           brew install --overwrite python@${{ matrix.python }}
-          echo /usr/local/opt/python@${{ matrix.python }}/libexec/bin/ >> $GITHUB_PATH
+          echo /opt/homebrew/opt/python@${{ matrix.python }}/libexec/bin/ >> $GITHUB_PATH
 
       - name: Install Ninja
         run: brew install ninja
 
-      - name: Update pip
-        # pip >= 23.0 fixes https://github.com/pypa/pip/issues/11539
-        run: python -m pip install --upgrade "pip >= 23.0"
-
       - name: Install Meson
         run: python -m pip install "meson ${{ matrix.meson }}"
         if: ${{ matrix.meson }}