chore: comment on the PR when a try is run

.github/workflows/try.yml

@@ -14,13 +14,32 @@ jobs:
     if: ${{  github.event.issue.pull_request && startsWith(github.event.comment.body, '/try') }}
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/github-script@v7
+        with:
+          script: |
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: "Okay, starting a try! I'll post anther comment once it starts..."
+            })
       - uses: xt0rted/pull-request-comment-branch@v2
         id: comment-branch
       - uses: "buildkite/[email protected]"
+        id: run-build
         with:
           buildkite_api_access_token: ${{ secrets.BUILDKITE_TOKEN }} # TODO(johnrwatson): This is Scott's Token at the minute, needs rotated
           pipeline: "system-initiative/si-merge-queue"
           branch: ${{ steps.comment-branch.outputs.head_ref }}
           message:  ":github: Try for branch ${{ steps.comment-branch.outputs.head_ref }}"
           ignore_pipeline_branch_filter: true
           send_pull_request: true
+      - uses: actions/github-script@v7
+        with:
+          script: |
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: "🚀 [Try running here](${{ steps.run-build.outputs.url }})! 🚀 "
+            })