Rewrite: ${GITHUB_OUTPUT} -> $GITHUB_OUTPUT.

.github/workflows/milestone-workflow.yml

@@ -41,11 +41,11 @@ jobs:
           echo version: $MILESTONE_VERSION
           if [[ $MILESTONE_VERSION =~ ^v[0-9]+\.[0-9]+\.0$ ]]; then
             echo 'This is NOT a patch release'
-            echo "is-patch=false" >> ${GITHUB_OUTPUT}
+            echo "is-patch=false" >> $GITHUB_OUTPUT
 
           elif [[ $MILESTONE_VERSION =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
             echo 'This is a patch release'
-            echo "is-patch=true" >> ${GITHUB_OUTPUT}
+            echo "is-patch=true" >> $GITHUB_OUTPUT
           else
             echo "Not a valid format of release, check the Milestone's title."
             echo 'Should be vX.Y.Z'