add image-builder workflow

Author: vomba

.github/workflows/build-image-builder.yml

@@ -0,0 +1,25 @@
+name: Build CAPI image builder
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+env:
+  TAG: ${{ github.ref_name }}
+  IMAGE_NAME: image-builder
+  REGISTRY: ghcr.io/elastisys 
+
+jobs:
+  build-image-builder:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: run make docker-build
+        run: make docker-build
+
+      - name: run make docker-push
+        run: make docker-push
+