add dockerhub publish action

.github/workflows/grpc-publish-to-dockerhub.yml

@@ -0,0 +1,39 @@
+name: gRPC publish to dockerhub
+
+on:
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: 'Tag to publish under, defaults to latest'
+        required: false
+        default: latest
+      branch:
+        description: 'Branch to run publish from'
+        required: true
+      dry-run:
+        description: 'Run in dry-run mode'
+        type: boolean
+        required: false
+        default: true
+
+jobs:
+  push_to_registry:
+    name: Push Docker image to Docker Hub
+    runs-on: ubuntu-latest
+    steps:
+    - name: Check out the repo
+      uses: actions/checkout@v4
+
+    - name: Log in to Docker Hub
+      uses: docker/login-action@f4ef78c080cd8ba55a85445d5b36e214a81df20a
+      with:
+        username: ${{ secrets.IOTALEDGER_DOCKER_USERNAME }}
+        password: ${{ secrets.IOTALEDGER_DOCKER_PASSWORD }}
+
+    - name: Build and push Docker image
+      uses: docker/build-push-action@3b5e8027fcad23fda98b2e3ac259d8d67585f671
+      with:
+        context: .
+        file: ./Dockerfile
+        push: ${{ !inputs.dry-run }}
+        labels: iotaledger/identity-grpc:${{ inputs.tag }}