Add GitHub workflow to create docker image for mlir-tensorrt project

This PR adds a GitHub workflow to create new docker image
if changes are made in `build_tools/docker/Dockerfile`,
`python/requirements-dev.txt` or `python/requirements.txt`.

.github/workflows/post-merge-container-update-mlir-tensorrt.yml

@@ -0,0 +1,116 @@
+name: Post-merge container update mlir-tensorrt
+
+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+
+on:
+  pull_requests:
+    branches:
+      - main
+  #push:
+  #  branches: [ "main" ]
+  #  paths: ['mlir-tensorrt/build_tools/docker/Dockerfile', 
+  #    'mlir-tensorrt/python/requirements-dev.txt',
+  #    'mlir-tensorrt/python/requirements.txt']
+
+env:
+  # Use docker.io for Docker Hub if empty
+  REGISTRY: ghcr.io
+  # github.repository as <account>/<repo>
+  IMAGE_NAME: ${{ github.repository }}
+  TAGS: ghcr.io/nvidia/tensorrt-incubator/mlir-tensorrt
+
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+      # This is used to complete the identity challenge
+      # with sigstore/fulcio when running outside of PRs.
+      id-token: write
+
+    steps:
+      # Based on https://stackoverflow.com/q/75536771
+      - name: Free disk space
+        run: |
+          sudo docker system prune -a -f
+          sudo rm -rf \
+            /usr/share/dotnet "$AGENT_TOOLSDIRECTORY" /usr/local/lib/android /opt/ghc \
+            /usr/local/share/powershell /usr/share/swift /usr/local/.ghcup \
+            /usr/lib/jvm
+
+          sudo apt-get purge microsoft-edge-stable || true
+          sudo apt-get purge google-cloud-cli || true
+          sudo apt-get purge dotnet-sdk-* || true
+          sudo apt-get purge google-chrome-stable || true
+
+          sudo apt-get autoremove -y
+          sudo apt-get autoclean -y
+
+      - name: Show disk usage
+        run: df . -h
+
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      # Install the cosign tool
+      # https://github.com/sigstore/cosign-installer
+      - name: Install cosign
+        uses: sigstore/cosign-installer@59acb6260d9c0ba8f4a2f9d9b48431a222b68e20 #v3.5.0
+        with:
+          cosign-release: 'v2.2.4'
+
+      # Set up BuildKit Docker container builder to be able to build
+      # multi-platform images and export cache
+      # https://github.com/docker/setup-buildx-action
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@f95db51fddba0c2d1ec667646a06c2ce06100226 # v3.0.0
+
+      # Login against a Docker registry
+      # https://github.com/docker/login-action
+      - name: Log into registry ${{ env.REGISTRY }}
+        uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # v3.0.0
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      # Extract metadata (tags, labels) for Docker
+      # https://github.com/docker/metadata-action
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@96383f45573cb7f253c731d3b3ab81c87ef81934 # v5.0.0
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+
+      # Build and push Docker image with Buildx
+      # https://github.com/docker/build-push-action
+      - name: Build and push Docker image
+        id: build-and-push
+        uses: docker/build-push-action@0565240e2d4ab88bba5387d719585280857ece09 # v5.0.0
+        with:
+          context: mlir-tensorrt/
+          file: mlir-tensorrt/build_tools/docker/Dockerfile
+          push: true
+          tags: ${{ env.TAGS }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+      # Sign the resulting Docker image digest.
+      # This will only write to the public Rekor transparency log when the Docker
+      # repository is public to avoid leaking data.  If you would like to publish
+      # transparency data even for private images, pass --force to cosign below.
+      # https://github.com/sigstore/cosign
+      - name: Sign the published Docker image
+        env:
+          # https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-an-intermediate-environment-variable
+          TAGS: ${{ env.TAGS }}
+          DIGEST: ${{ steps.build-and-push.outputs.digest }}
+        # This step uses the identity token to provision an ephemeral certificate
+        # against the sigstore community Fulcio instance.
+        run: echo "${TAGS}" | xargs -I {} cosign sign --yes {}@${DIGEST}