Artifact push actually happens on branch, not tag

Signed-off-by: Bob Weinand <[email protected]>

Author: bwoebi

.github/chainguard/gitlab-ci-publish-release.sts.yaml

@@ -1,6 +1,6 @@
 issuer: https://gitlab.ddbuild.io
 
-subject_pattern: "project_path:DataDog/apm-reliability/dd-trace-php:ref_type:tag:ref:ddtrace-.*"
+subject_pattern: "project_path:DataDog/apm-reliability/dd-trace-php:ref_type:branch:ref:ddtrace-.*"
 
 permissions:
   contents: write