use github runner

.github/workflows/docker-build.yaml

@@ -9,9 +9,15 @@ on:
 
 jobs:
   build:
-    runs-on: self-hosted
+    runs-on: ubuntu-latest
     steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
       - name: Build Docker image
-        run: docker build -t nextjs-app:latest .
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: false
+          tags: nextjs-app:latest
+          cache-from: type=gha
+          cache-to: type=gha,mode=max