Modernize docker build and secrets checks

.github/workflows/deploy.yml

@@ -10,23 +10,34 @@ on:
       - deploy
 
 jobs:
-  deploy:
-    name: Build and deploy
+
+  check-secrets:
     runs-on: ubuntu-latest
+    outputs:
+      HAS_SECRETS: ${{ steps.check.outputs.HAS_SECRETS }}
     steps:
-
-      - name: Install Docker
-        run: |
-          curl -fsSL https://get.docker.com -o get-docker.sh
-          sh get-docker.sh
-
-      - name: Build Docker image
+      - id: check
         env:
           DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
           DOCKERHUB_PASSWORD: ${{ secrets.DOCKERHUB_PASSWORD }}
-        if: ${{ env.DOCKERHUB_USERNAME && env.DOCKERHUB_PASSWORD  }}
-        run: |
-          echo "$DOCKERHUB_PASSWORD" | docker login -u "$DOCKERHUB_USERNAME" --password-stdin
-          docker build -t kspckan/mod-installer .
-          docker tag kspckan/mod-installer kspckan/mod-installer:latest
-          docker push kspckan/mod-installer:latest
+        run: |-
+          echo "::set-output name=HAS_SECRETS::${{ env.DOCKERHUB_USERNAME != '' && env.DOCKERHUB_PASSWORD != '' }}"
+
+  deploy:
+    name: Build and deploy
+    needs: check-secrets
+    if: needs.check-secrets.outputs.HAS_SECRETS
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_PASSWORD }}
+      - name: Build ModInstaller image
+        uses: docker/build-push-action@v5
+        with:
+          tags: kspckan/mod-installer
+          outputs: type=registry