Improve CI

Add more tests to the CI, including a docker build test, and add the
generation and publication of a new docker image on master and tags

.drone.yml

@@ -51,7 +51,9 @@ trigger:
 # On a tag, only build the related docker image
 kind: pipeline
 type: docker
-name: Release
+name: tag-release
+depends_on:
+  - test-build
 
 steps:
 - name: docker-push-tag