actions: Rewrite/cleanup and upgrade

Author: FloatingMilkshake

.github/workflows/docker-build.yml

@@ -0,0 +1,39 @@
+name: docker-build
+
+on:
+  push:
+  pull_request:
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Log in to GitHub Container Registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v4
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v4
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v7
+        with:
+          context: .
+          platforms: linux/amd64, linux/arm64
+          push: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}
+          tags: ghcr.io/floatingmilkshake/mechanicalmilkshake:latest