Drop usage of docker plugin

Because the plugin uses old version of docker not compatible with new Debian

.drone.yml

@@ -4,13 +4,16 @@ name: image building
 
 steps:
 - name: build&push
-  image: plugins/docker
-  settings:
+  image: harbor.hq.rosti.cz/library/builder:35
+  environment:
     username: robot$library+droneci
     password: 
       from_secret: repo_password
     repo: harbor.hq.rosti.cz/library/builder
-    registry: harbor.hq.rosti.cz
-    tags:
-    - 35
-    - latest
+    tag: 35
+  commands:
+  - echo $password | podman login -u $username --password-stdin harbor.hq.rosti.cz
+  - podman build -t $repo:$tag .
+  - podman tag $repo:$tag $repo:latest
+  - podman push $repo:$tag
+  - podman push $repo:latest