chore: add workflow to build action image (#16)

Author: AnActualEmerald

.github/workflows/build.yml

@@ -0,0 +1,28 @@
+name: Docker Image CI
+
+on:
+  workflow_dispatch:
+  release: 
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Build the Docker image
+      run: docker build . --file Dockerfile --tag localhost/utp:dev-${{github.run_number}}
+    - name: Authenticate with GHCR
+      if: github.event_name == 'release'
+      uses: docker/login-action@v2.1.0
+      with:
+        registry: ghcr.io
+        username: greentf
+        password: ${{ secrets.GITHUB_TOKEN }}
+    - name: Push container
+      if: github.event_name == 'release'
+      run: docker push localhost/utp:dev-${{github.run_number}} ghcr.io/greentf/utp:latest