Create new build-publish workflow for chainlink-untrusted (from PR)

.github/workflows/build-publish-pr.yml

@@ -0,0 +1,44 @@
+name: "Build and Publish from PR"
+
+##
+# This workflow builds and publishes a Docker image for Chainlink from a PR.
+# It doesn't use an environment, has its own special IAM role, does not sign
+# the image, and publishes to a special ECR repo.
+##
+
+on:
+  pull_request:
+
+jobs:
+  build-publish-untrusted:
+    if: ${{ ! startsWith(github.ref_name, 'release/') }}
+    runs-on: ubuntu-20.04
+    permissions:
+      id-token: write
+      contents: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+
+      - name: Build, sign and publish chainlink image
+        uses: ./.github/actions/build-sign-publish-chainlink
+        with:
+          publish: true
+          aws-role-to-assume: ${{ secrets.AWS_OIDC_IAM_ROLE_PUBLISH_PR_ARN }}
+          aws-role-duration-seconds: ${{ secrets.AWS_ROLE_DURATION_SECONDS_DEFAULT }}
+          aws-region: ${{ secrets.AWS_REGION }}
+          sign-images: false
+          ecr-hostname: ${{ secrets.AWS_SDLC_ECR_HOSTNAME }}
+          ecr-image-name: chainlink-untrusted
+          dockerhub_username: ${{ secrets.DOCKERHUB_READONLY_USERNAME }}
+          dockerhub_password: ${{ secrets.DOCKERHUB_READONLY_PASSWORD }}
+
+      - name: Collect Metrics
+        if: always()
+        id: collect-gha-metrics
+        uses: smartcontractkit/push-gha-metrics-action@d1618b772a97fd87e6505de97b872ee0b1f1729a # v2.0.2
+        with:
+          basic-auth: ${{ secrets.GRAFANA_CLOUD_BASIC_AUTH }}
+          hostname: ${{ secrets.GRAFANA_CLOUD_HOST }}
+          this-job-name: build-publish-untrusted
+        continue-on-error: true