added new workflow

.github/workflows/publish-ghcr.yaml

@@ -0,0 +1,15 @@
+name: Docker Image CI for GHCR
+
+on:
+  push
+
+jobs:
+  build_and_publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Build and push the image
+        run: |
+          docker login --username broizter --password {{ secrets.GH_PAT }} ghcr.io
+          docker build . --tag ghcr.io/broizter/ssh-server-on-docker-with-docker:latest
+          docker push ghcr.io/broizter/ssh-server-on-docker-with-docker:latest