Fetch refs for successful testing for tag (go-gitea#7388)

* Fetch refs for successful testing for tag

Fix go-gitea#7382

* Update .drone.yml

Author: techknowlogick

.drone.yml

@@ -116,6 +116,17 @@ steps:
         - push
         - pull_request
 
+  - name: tag-pre-condition
+    pull: always
+    image: alpine/git
+    commands:
+      - git update-ref refs/heads/tag_test ${DRONE_COMMIT_SHA}
+    depends_on:
+      - build
+    when:
+      event:
+        - tag
+
   - name: tag-test
     pull: always
     image: golang:1.12
@@ -124,7 +135,7 @@ steps:
     environment:
       TAGS: bindata
     depends_on:
-      - build
+      - tag-pre-condition
     when:
       event:
         - tag