ci: write PR sts-Octo - include ref path (#1533)

# What does this PR do?

Include ref path

Author: iunanua

.github/chainguard/self.write.pr.sts.yaml

@@ -3,7 +3,7 @@ issuer: https://token.actions.githubusercontent.com
 subject_pattern: "repo:DataDog/libdatadog.*"
 
 claim_pattern:
-  ref: "(main|release)"
+  ref: "refs/heads/(main|release)"
   ref_protected: "true"
   # job_workflow_ref: DataDog/libdatadog/\.github/workflows/release-proposal-dispatch\.yml@.+