Create CI to build container

.github/workflows/build-image.yml

@@ -0,0 +1,13 @@
+name: Build Image
+
+on:
+  push:
+    branches: [ "master" ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: Build the Docker image
+      run: docker build . --tag papermc:$(date +%s)