docs: push on tag

Author: casperdcl

.github/workflows/build.yml

@@ -176,7 +176,7 @@ jobs:
         name: DocumentationHTML
         path: docs/build
     - name: Push changes
-      if: github.ref == 'refs/heads/master'
+      if: github.ref == 'refs/heads/master' || startsWith(github.ref, 'refs/tags')
       uses: casperdcl/push-dir@v1
       with:
         message: Update documentation