Added action for building keygenerator docker images

.github/workflows/deploy-docker.yaml

@@ -0,0 +1,40 @@
+env:
+  IMAGE_NODE: chain-keygenerator
+  REGISTRY_HOSTNAME: multiversx
+
+name: Build Docker image & push
+
+on:
+  workflow_dispatch:
+  pull_request:
+
+jobs:
+  build-docker-image:
+    strategy:
+      matrix:
+        runs-on: [ubuntu-latest]
+    runs-on: ${{ matrix.runs-on }}
+
+    steps:
+      - name: Check out code into the Go module directory
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log into Docker Hub
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push image to Docker Hub
+        id: push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          file: ./docker/keygenerator/Dockerfile
+          platforms: linux/amd64,linux/arm64
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ env.REGISTRY_HOSTNAME }}/${{ env.IMAGE_NODE }}:latest