build: Switch to kaniko plugin

.drone.yml

@@ -6,13 +6,13 @@ steps:
 - name: Build & publish (Harbor)
   depends_on:
   - clone
-  image: plugins/docker
+  image: plugins/kaniko
   context: .
   settings:
-    repo: bv11-cr01.bessems.eu/library/json-server
+    repo: library/json-server
     registry: bv11-cr01.bessems.eu
     tags: latest
-    mtu: 1450
+    # mtu: 1450
     username:
       from_secret: harbor_username
     password:
@@ -20,12 +20,13 @@ steps:
 - name: Build & publish (Dockerhub)
   depends_on:
   - clone
-  image: plugins/docker
+  image: plugins/kaniko
   context: .
   settings:
     repo: djpbessems/json-server
+    registry: docker.io
     tags: latest
-    mtu: 1450
+    # mtu: 1450
     username:
       from_secret: docker_username
     password: