feat: publish docker img from CI

.env-sample

@@ -0,0 +1,2 @@
+export FORGEJO_URL="http://localhost:7000"
+export FORGEJO_SSH_URL="ssh://git@localhost:2222"

.woodpecker.yml

@@ -0,0 +1,20 @@
+pipeline:
+  build_docker_img:
+    image: plugins/docker
+    when:
+      event: [pull_request]
+    settings:
+      dry_run: true
+      repo: forgeflux/forgejo-init-script
+      tags: latest
+
+  build_and_publish_docker_img:
+    image: plugins/docker
+    when:
+      event: [push, tag, deployment]
+    settings:
+      username: forgeflux
+      password:
+        from_secret: DOCKER_TOKEN
+      repo: forgeflux/forgejo-init-script
+      tags: latest