update drone discord plugin to 0.0.4 version (#1992)

* update drone discord plugin to 0.0.3 version

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update to 0.0.4

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* update sig file.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

.drone.yml

@@ -166,7 +166,7 @@ pipeline:
       branch: [ refs/tags/* ]
 
   discord:
-    image: appleboy/drone-discord
+    image: appleboy/drone-discord:0.0.4
     webhook_id: ${WEBHOOK_ID}
     webhook_token: ${WEBHOOK_TOKEN}
     when: