Update update_docs

Author: beckermr

.ci_scripts/update_docs

@@ -35,7 +35,7 @@ if [ -n "$GH_TOKEN" ]; then
 
     # Only commit the docs for commits on master.
     # GITHUB_HEAD_REF is empty on forks
-    if [[ "$GH_REF" == "ref/heads/master" ]] && [[ "$GH_HEAD_REF" == "" ]]; then
+    if [[ "$GH_REF" == "ref/heads/master" ]] && [[ "$GH_ACTOR" == "conda-forge" ]]; then
         git add -A :/
         git commit -m "Re-ran make.py. [ci skip]" || true
         git remote add pushable https://${GH_TOKEN}@github.com/conda-forge/conda-forge.github.io.git/ > /dev/null