updated workflow

.github/workflows/deploy_docs.yml

@@ -14,10 +14,10 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
 
@@ -33,7 +33,7 @@ jobs:
           mkdocs build  # twice, see https://github.com/patrick-kidger/pytkdocs_tweaks
 
       - name: Upload docs
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: docs
           path: site  # where `mkdocs build` puts the built site