fix: Replace Docker Hub docker image hosting with GitHub package

.github/workflows/docker.yml

@@ -0,0 +1,42 @@
+name: Docker Publish
+
+on:
+  push:
+    tags:
+      - "*"
+
+permissions:
+  contents: read
+  packages: write
+
+jobs:
+  publish:
+    name: Build & upload Docker image
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download source
+        uses: actions/checkout@v3
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract Docker metadata
+        uses: docker/metadata-action@v4
+        id: meta
+        with:
+          images: ghcr.io/${{ github.repository_owner }}/udl-server
+          tags: |
+            type=raw,value=latest,enable=true
+            type=ref,event=tag
+
+      - name: Build & upload Docker image
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

README.md

@@ -75,7 +75,7 @@ The project makes it easy for you to self host a UDL Server. The easiest way to
       - Enable activity continuation and other [associated domain features](https://developer.apple.com/documentation/xcode/supporting-associated-domains)
       - i.e. `ABCDE12345.com.example.app`
 
-Alternatively you can run the lightweight [`fdocr/udl-server`](https://hub.docker.com/repository/docker/fdocr/udl-server) Docker container on your own. At the time of this writing the docker image is only about `26.3 MB` in size (`10.87 MB` compressed).
+Alternatively you can run the lightweight [`ghcr.io/fdocr/udl-server`](https://ghcr.io/fdocr/udl-server) Docker container on your own. At the time of this writing the docker image is only about `26.3 MB` in size (`10.87 MB` compressed).
 
 ## Troubleshooting