drone: fix build process

We need to build the binary on tag so it can be included in the docker
image.

Author: fsouza

drone/ci.jsonnet

@@ -101,7 +101,7 @@ local build(go_version) = {
   environment: { CGO_ENABLED: '0' },
   depends_on: ['mod-download'],
   when: {
-    event: ['pull_request', 'push'],
+    event: ['pull_request', 'push', 'tag'],
   },
 };
 

drone/ci.yml

@@ -51,6 +51,7 @@ steps:
     event:
     - pull_request
     - push
+    - tag
   depends_on:
   - mod-download
 
@@ -165,6 +166,7 @@ steps:
     event:
     - pull_request
     - push
+    - tag
   depends_on:
   - mod-download