Update generate_documentation.yml

.github/workflows/generate_documentation.yml

@@ -8,9 +8,9 @@ jobs:
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Setup cache
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/SpacemanDMM
           key: ${{ runner.os }}-spacemandmm-${{ secrets.CACHE_PURGE_KEY }}