Fix cache key creation for macos release

Author: dunkmann00

.github/workflows/notifications.yml

@@ -71,7 +71,7 @@ jobs:
         run: |
           CACHE_KEY_PREFIX="mac-notifications"
           if [ "$GITHUB_EVENT_NAME" == "release" ]; then
-            $CACHE_KEY_PREFIX="$CACHE_KEY_PREFIX-release"
+            CACHE_KEY_PREFIX="$CACHE_KEY_PREFIX-release"
           fi
           echo "CACHE_KEY_PREFIX=$CACHE_KEY_PREFIX" >> "$GITHUB_ENV"
       - name: Cache macOS Notification App