Add CI for Docker images

.github/workflows/ci-docker.yml

@@ -0,0 +1,25 @@
+name: CI (Docker image)
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: 'recursive'
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+      - name: Set up buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Build image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64,linux/arm/v7,windows/amd64
+          push: false
+          pull: true
+          cache-from: type=gha, scope=${{ github.workflow }}
+          cache-to: type=gha, scope=${{ github.workflow }}

docs/changelog.md

@@ -90,6 +90,7 @@ Use past tense when adding new entries; sign your name off when you add or chang
 * Added a property `TSPlayer.Hostile`, which gets pvp player mode. (@AgaSpace)
 * Fixed typo in `/gbuff`. (@sgkoishi, #2955)
 * Rewrote the `.dockerignore` file into a denylist. (@timschumi)
+* Added CI for Docker images. (@timschumi)
 
 ## TShock 5.2
 * An additional option `pvpwithnoteam` is added at `PvPMode` to enable PVP with no team. (@CelestialAnarchy, #2617, @ATFGK)