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

@@ -3,12 +3,38 @@ type: docker
 name: Tests
 
 steps:
-- name: test
+- name: go-test
   image: golang
   commands:
-  - cd tracker
-  - make build
-  - make test
+  - make -C tracker test
+  depends_on:
+
+- name: go-build
+  image: golang
+  commands:
+  - make -C tracker build
+  depends_on:
+
+- name: docker-build
+  image: thegeeklab/drone-docker-buildx
+  privileged: true
+  settings:
+    repo: git.faercol.me/faercol/public-ip-tracker
+    tags: latest
+    platforms:
+      - linux/amd64
+      - linux/arm64
+  depends_on:
+
+- name: docker-push
+  image: thegeeklab/drone-docker-buildx
+  privileged: true
+  settings:
+    repo: git.faercol.me/faercol/public-ip-tracker
+  depends_on:
+    - go-test
+    - go-build
+    - docker-build
 
 trigger:
   event: