[ci] Fix for dubious repo ownership issue (#1840)

.github/workflows/build_docs.yml

@@ -21,6 +21,7 @@ jobs:
         apt-get update
         apt-get install -y git
         git clone "https://token:${GITHUB_TOKEN}@github.com/${GITHUB_REPOSITORY}.git" .
+        git config --global --add safe.directory /__w/${GITHUB_REPOSITORY}/${GITHUB_REPOSITORY}
       shell: bash
 
     - name: Execute script to build our documentation and update pages