fix “git.too_shallow” in docs building?

Author: rickwierenga

.github/workflows/docs.yml

@@ -14,6 +14,8 @@ jobs:
     steps:
       - name: Checkout Code
         uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
 
       - name: Update packages
         run: sudo apt-get update