Correct yml syntax

Author: bbimber

.github/workflows/sync-repos.yml

@@ -4,7 +4,8 @@ on:
     - cron:  "10 */3 * * *"
 jobs:
   sync-release-branches:
-    if: github.head_ref == ""
+    # github.head_ref should only be set on forked repos, meaning this action should only run on the primary fork
+    if: !github.head_ref
     runs-on: ubuntu-latest
     steps:
       - name: "Sync Release Branches"
@@ -16,7 +17,7 @@ jobs:
           destination_branch_prefix: "discvr-"
           github_token: ${{ secrets.GITHUB_TOKEN }}
   sync-develop:
-    if: github.head_ref == ""
+    if: !github.head_ref
     runs-on: ubuntu-latest
     steps:
       - name: "Sync Develop Branch"