ci: avoid broken pip in CI jobs

see pypa/pip#10851

.github/workflows/dependencies.yml

@@ -83,7 +83,7 @@ jobs:
       if: matrix.experimental == true
       run: |
         sudo apt-get -y -q install libkrb5-dev
-        python -m pip install -U pip wheel
+        python -m pip install -U "pip!=22.0" wheel
         python -m pip install -r requirements.txt --upgrade --upgrade-strategy=eager --pre
 
     - name: Install GWpy