Add build workflow

.gitea/workflows/build.yaml

@@ -0,0 +1,32 @@
+name: Build morthimer/caddy-homelab image
+on: [push]
+env:
+  REPOSITORY: git.int.morthimer.fr:8443
+
+job:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Repository checkout
+        uses: actions/checkout@v4
+      - name: Lint Dockerfile with Hadolint
+        uses: hadolint/hadolint-action@v3.1.0
+        with:
+          dockerfile: Dockerfile
+
+  build:
+    needs: lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: Repository login
+        uses: docker/login-action@v3
+        with:
+          registry: $REPOSITORY
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Build and push image
+        uses: docker/build-push-action@v5
+        with:
+          push: true
+          tags: $REPOSITORY/${{ gitea.repository }}:latest