fix(gha): set vcs.ref.head.name correctly on PR (#77)

For pull requests, this is not set to the head branch but to pull/XX

pytest_mergify/resources/github_actions.py

@@ -25,12 +25,15 @@ def get_github_actions_head_sha() -> str | None:
                 return str(event["pull_request"]["head"]["sha"])
         return os.getenv("GITHUB_SHA")
 
+    @staticmethod
+    def get_github_head_ref_name() -> str | None:
+        return os.getenv("GITHUB_HEAD_REF") or os.getenv("GITHUB_REF")
+
     OPENTELEMETRY_GHA_MAPPING = {
         cicd_attributes.CICD_PIPELINE_NAME: (str, "GITHUB_JOB"),
         cicd_attributes.CICD_PIPELINE_RUN_ID: (int, "GITHUB_RUN_ID"),
         "cicd.pipeline.run.attempt": (int, "GITHUB_RUN_ATTEMPT"),
         cicd_attributes.CICD_PIPELINE_TASK_NAME: (str, "GITHUB_ACTION"),
-        vcs_attributes.VCS_REF_HEAD_NAME: (str, "GITHUB_REF_NAME"),
         vcs_attributes.VCS_REF_HEAD_TYPE: (str, "GITHUB_REF_TYPE"),
         vcs_attributes.VCS_REF_BASE_NAME: (str, "GITHUB_BASE_REF"),
         "vcs.repository.name": (str, "GITHUB_REPOSITORY"),
@@ -48,6 +51,10 @@ def detect(self) -> Resource:
                 os.environ["GITHUB_SERVER_URL"] + "/" + os.environ["GITHUB_REPOSITORY"]
             )
 
+        head_ref = self.get_github_head_ref_name()
+        if head_ref is not None:
+            attributes[vcs_attributes.VCS_REF_HEAD_NAME] = head_ref
+
         head_sha = self.get_github_actions_head_sha()
         if head_sha is not None:
             attributes[vcs_attributes.VCS_REF_HEAD_REVISION] = head_sha