replace PR docker dry run in drone with Actions (#24475)

As before with past PRs to switch Drone pipelines to use (GitHub)
Actions.

---------

Co-authored-by: silverwind <me@silverwind.io>

.drone.yml

@@ -1306,43 +1306,6 @@ steps:
         exclude:
         - pull_request
 
----
-kind: pipeline
-type: docker
-name: docker-linux-arm64-dry-run
-
-platform:
-  os: linux
-  arch: arm64
-
-depends_on:
-  - compliance
-
-trigger:
-  event:
-    - pull_request
-  paths:
-    exclude:
-      - "docs/**"
-
-steps:
-  - name: dryrun
-    image: plugins/docker:latest
-    pull: always
-    settings:
-      dry_run: true
-      repo: gitea/gitea
-      tags: linux-arm64
-      build_args:
-        - GOPROXY=https://goproxy.io
-    environment:
-      PLUGIN_MIRROR:
-        from_secret: plugin_mirror
-      DOCKER_BUILDKIT: 1
-    when:
-      event:
-        - pull_request
-
 ---
 kind: pipeline
 type: docker

.github/workflows/pull-docker_dryrun.yml

@@ -0,0 +1,19 @@
+name: Docker build dry run
+
+on: [pull_request]
+
+jobs:
+  docker_dryrun:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v3
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Build and push
+        uses: docker/build-push-action@v4
+        with:
+          push: false
+          tags: gitea/gitea:linux-amd64
+          build-args: |
+            GOPROXY=https://goproxy.io