See if introducing HEAD in workflow helps with weird comparison to main branch

Author: blewis12

.github/workflows/check-sync-module-dependencies.yml

@@ -31,15 +31,15 @@ jobs:
       - name: Check for go.mod changes
         run: |
           # List changed go.mod files (added/modified/deleted)
-          CHANGED=$(git diff --name-only --ignore-all-space | grep -E '(^|/)go\.mod$' || true)
+          CHANGED=$(git diff --name-only --ignore-all-space HEAD | grep -E '(^|/)go\.mod$' || true)
 
           if [ -n "$CHANGED" ]; then
             echo "::error::go.mod files are out of sync with generate-module-dependencies."
             echo "The following go.mod files changed:"
             echo "$CHANGED"
             echo
             echo "Diff:"
-            git --no-pager diff -- $CHANGED || true
+            git --no-pager diff HEAD -- $CHANGED || true
             echo
             echo "To fix locally:"
             echo "  Ensure that you update the dependency-replacements.yaml file and run make generate-module-dependencies"