Pin python<3.12 in hooks to install dependencies

Some libraries are only supported for python <= 3.12 this sets the
python version to 3.12 for the docs and validate_examples hooks so that
Ray gets installed.

.github/workflows/docs.yml

@@ -23,6 +23,8 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v3
+        with:
+          python-version: '3.12'
       - name: Install dependencies
         run: |
           pip install -e ".[documentation]"

.github/workflows/python-package.yml

@@ -52,6 +52,8 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v3
+        with:
+          python-version: '3.12'
       - name: Install dependencies
         run: |
           python -m pip install -e ".[tests]"