ci: Add Docker Hub image push to workflow

Author: splitbrain

.github/workflows/docker-build.yml

@@ -41,12 +41,20 @@ jobs:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
+          
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Extract metadata for Docker
         id: meta
         uses: docker/metadata-action@v5
         with:
-          images: ghcr.io/${{ github.repository }}
+          images: |
+            ghcr.io/${{ github.repository }}
+            ${{ secrets.DOCKERHUB_USERNAME }}/${{ github.event.repository.name }}
           tags: |
             type=semver,pattern={{version}}
             type=semver,pattern={{major}}.{{minor}}