Merge pull request #2602 from ReactionMechanismGenerator/bad_pudding

fix checkout command for docs building action

Author: hwpang

.github/workflows/docs.yml

@@ -43,6 +43,10 @@ jobs:
           cd RMG-Py
           sed -i '/embedsignature/s/# //g' setup.py
           make
+      - uses: actions/checkout@v2
+        with:
+          ref: gh-pages
+          path: build/html
       - name: Make documentation - for testing
         if: ${{  github.event_name != 'push' || github.repository != 'ReactionMechanismGenerator/RMG-Py' }}
         run: |
@@ -58,8 +62,6 @@ jobs:
           git config user.name github-actions
           git config user.email [email protected]
           cd documentation
-          rm -rf build/html
-          git clone --single-branch --branch gh-pages --origin official [email protected]:ReactionMechanismGenerator/RMG-Py.git build/html
           make html
       - name: Check documentation links
         continue-on-error: true