diff --git a/generate-docker-image-tags/action.yml b/generate-docker-image-tags/action.yml
index 6debbeb..a9b4a3b 100644
--- a/generate-docker-image-tags/action.yml
+++ b/generate-docker-image-tags/action.yml
@@ -68,7 +68,7 @@ runs:
         then
           # Workflow was triggered by a "push" event.
           PR_NUMBER=$( \
-            (echo "${{ github.event.head_commit.message }}" \
+            (echo '${{ github.event.head_commit.message }}' \
             | grep -o "\(#[0-9]\+\)" || true) \
             | sed "s/[#()]//g" \
           )