Update actions versions (#2260)

Fix GitHub Actions Node.js deprecation warnings.

Use actions/setup-python cache where appropriate.

.github/workflows/documentation.yml

@@ -8,13 +8,14 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: "Checkout Instaloader Repository"
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0  # needed for building docs
       - name: "Setup Python"
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v5
         with:
           python-version: 3.12
+          cache: 'pipenv'
       - name: "Install Dependencies"
         run: |
           python -m pip install pipenv==2023.12.1