Support Dispatch Build (#5)

Author: takanotaiga

.github/workflows/docker_build_main.yaml .github/workflows/docker_build.yaml.github/workflows/docker_build_main.yaml renamed to .github/workflows/docker_build.yaml

@@ -5,12 +5,15 @@ on:
   schedule:
     - cron: '0 14 * * *'
   push:
-    branches:
-      - main
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+  repository_dispatch:
+    types: [dispatches]
 
 permissions:
   contents: write
-  packages: write  # GHCR への Push に必要
+  packages: write
 
 jobs:
   build-and-push:
@@ -34,7 +37,7 @@ jobs:
         uses: docker/build-push-action@v5
         with:
           context: .
-          push: true
+          push: ${{ github.event_name != 'pull_request' }}
           tags: |
             ghcr.io/minecraft-ros2/ros2_java:latest
           labels: |