Do not publish frontend plugin to github releases (#2663)

# What this PR does

## Which issue(s) this PR fixes

## Checklist

- [ ] Unit, integration, and e2e (if applicable) tests updated
- [ ] Documentation added (or `pr:no public docs` PR label added if not
required)
- [ ] `CHANGELOG.md` updated (or `pr:no changelog` PR label added if not
required)

.drone.yml

@@ -34,19 +34,6 @@ steps:
       - zip -r grafana-oncall-app.zip ./grafana-oncall-app
       - if [ -z "$DRONE_TAG" ]; then echo "No tag, skipping archive"; else cp grafana-oncall-app.zip grafana-oncall-app-${DRONE_TAG}.zip; fi
 
-  - name: Publish Plugin to Github (release)
-    image: plugins/github-release
-    settings:
-      api_key:
-        from_secret: gh_token
-      files: grafana-plugin/ci/dist/grafana-oncall-app-${DRONE_TAG}.zip
-      title: ${DRONE_TAG}
-    depends_on:
-      - Sign and Package Plugin
-    when:
-      ref:
-        - refs/tags/v*.*.*
-
   - name: Publish Plugin to GCS (release)
     image: plugins/gcs
     settings:
@@ -279,14 +266,6 @@ get:
   path: infra/data/ci/gcr-admin
   name: .dockerconfigjson
 
----
-# Secret for GitHub
-get:
-  name: pat
-  path: infra/data/ci/github/grafanabot
-kind: secret
-name: gh_token
-
 ---
 # Slack webhook
 get:
@@ -334,6 +313,6 @@ kind: secret
 name: drone_token
 ---
 kind: signature
-hmac: 1ca79af7b8ada54237e4fb78fffb9314babc00b3a8a4866ec454d32356bc067b
+hmac: f09cde0461e15ca192f16ffb9d92f802ed127988643581e95a2fbdbba720fb89
 
 ...