Update fetch

.github/workflows/docs.yml

@@ -12,7 +12,7 @@ jobs:
       - name: Check if docs changed
         id: changes
         run: |
-          git fetch origin main
+          git fetch --all
           git diff --quiet origin/main -- docs
           echo ::set-output name=docs::$(test $? -ne 0 && echo 'true' || echo 'false')
       - uses: actions/setup-python@v2