CI: build llm-load-test image on every merge

This commit builds a container image with each
code change and stores it in the GH registry.

.github/workflows/build.yml

@@ -0,0 +1,37 @@
+---
+name: publish
+on: [push]
+permissions:
+  contents: read
+  packages: write
+env:
+  REGISTRY_USER: ${{ github.actor }}
+  REGISTRY_PASSWORD: ${{ github.token }}
+  IMAGE_REGISTRY: ghcr.io/${{ github.repository_owner }}
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      max-parallel: 4
+      matrix:
+        python-version: [3.9]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Buildah build
+        id: build-image
+        uses: redhat-actions/buildah-build@v2
+        with:
+          image: ${{ github.event.repository.name }}
+          tags: latest ${{ github.sha }}
+          containerfiles: |
+            ./build/Containerfile
+      - name: Push To ghcr.io
+        id: push-to-ghcr
+        uses: redhat-actions/push-to-registry@v2
+        with:
+          image: ${{ steps.build-image.outputs.image }}
+          tags: ${{ steps.build-image.outputs.tags }}
+          username: ${{ env.REGISTRY_USER }}
+          password: ${{ env.REGISTRY_PASSWORD }}
+          registry: ${{ env.IMAGE_REGISTRY }}