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

@@ -17,35 +17,48 @@ steps:
   - make -C tracker build
   depends_on:
 
-- name: docker-build
+- name: docker-build-only
   image: thegeeklab/drone-docker-buildx
   privileged: true
   settings:
     repo: git.faercol.me/faercol/public-ip-tracker
     tags: latest
+    dry_run: true
     platforms:
       - linux/amd64
       - linux/arm64
   depends_on:
+  when:
+    branch:
+      exclude:
+        - master
+    event:
+      - push
 
-- name: docker-push
+- name: docker-build-push
   image: thegeeklab/drone-docker-buildx
   privileged: true
   settings:
     repo: git.faercol.me/faercol/public-ip-tracker
     registry: git.faercol.me
     tags: latest
-    username: faercol
+    username:
+      from_secret: GIT_USERNAME
     password:
       from_secret: GIT_PASSWORD
   depends_on:
     - go-test
     - go-build
-    - docker-build
+  when:
+    branch:
+      - master
+    event:
+      - push
 
 trigger:
   event:
     - push
+    - tag
 
 ---
 # On a tag, only build the related docker image
@@ -63,7 +76,8 @@ steps:
     registry: git.faercol.me
     repo: git.faercol.me/faercol/public-ip-tracker
     auto_tag: true
-    username: faercol
+    username:
+      from_secret: GIT_USERNAME
     password:
       from_secret: GIT_PASSWORD