Adding github action

.github/workflows/main.yml

@@ -0,0 +1,19 @@
+name: build-container
+
+on: push
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Docker setup
+        uses: docker/setup-buildx-action@v3
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: ./Dockerfile
+          push: false
+          tags: eigenlayer-payment-updater:${{ github.sha }}