Optionally skip ci based on a label in the pr (#1444)

* Adds a `get-pr-info` job at the head of the pipeline which examines the labels on the PR.
* If the PR contains the `skip-ci` label, the rest of the jobs in the CI pipeline are skipped.
* This avoids the requirement to include `[no ci]` in commit comments. 
* After the label is removed CI will execute on the next push.

Closes #1183

## By Submitting this PR I confirm:
- I am familiar with the [Contributing Guidelines](https://github.com/nv-morpheus/Morpheus/blob/main/docs/source/developer_guide/contributing.md).
- When the PR is ready for review, new or existing tests cover these changes.
- When the PR is ready for review, the documentation is up to date with these changes.

Authors:
  - David Gardner (https://github.com/dagardner-nv)

Approvers:
  - Michael Demoret (https://github.com/mdemoret-nv)

URL: #1444

.github/workflows/pull_request.yml

@@ -42,8 +42,28 @@ permissions:
   statuses: none
 
 jobs:
+  prepare:
+    # Executes the get-pr-info action to determine if the PR has the skip-ci label, if the action fails we assume the
+    # PR does not have the label
+    name: Prepare
+    runs-on: ubuntu-latest
+    container:
+      image: rapidsai/ci-conda:latest
+    steps:
+      - name: Get PR Info
+        id: get-pr-info
+        uses: rapidsai/shared-action-workflows/[email protected]
+        if: ${{ startsWith(github.ref_name, 'pull-request/') }}
+    outputs:
+      has_skip_ci_label: ${{ steps.get-pr-info.outcome == 'success' && contains(fromJSON(steps.get-pr-info.outputs.pr-info).labels.*.name, 'skip-ci') || false }}
+
   ci_pipe:
+    name: CI Pipeline
+    needs: [prepare]
     uses: ./.github/workflows/ci_pipe.yml
+
+    # Only run the CI pipeline if the PR does not have the skip-ci label
+    if: ${{ ! fromJSON(needs.prepare.outputs.has_skip_ci_label) }}
     with:
       run_check: ${{ startsWith(github.ref_name, 'pull-request/') }}
       container: nvcr.io/ea-nvidia-morpheus/morpheus:morpheus-ci-build-230913