Update .gitlab/generate-package.php

Author: erikayasuda

.gitlab/generate-package.php

@@ -1709,7 +1709,7 @@ function appsec_image_from_tag_mapping(string $tag): string
   needs:
     - job: "bundle for reliability env"
   rules:
-    - if: $NIGHTLY_BUILD
+    - if: $NIGHTLY_BUILD == "true"
       when: on_success
     - when: manual
       allow_failure: true