chore(deps): update actions/setup-python action to v4

Author: renovate[bot]

.github/workflows/docs.yml

@@ -27,7 +27,7 @@ jobs:
       - changes
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
+      - uses: actions/setup-python@v4
         with:
           python-version: 3.x
       - run: pip install mkdocs-material==8.0.2
@@ -43,7 +43,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
+      - uses: actions/setup-python@v4
         with:
           python-version: 3.x
       - run: pip install mkdocs-material==8.0.2