Use comment_tag to update benchmark action comment (#553)

Author: adam-fowler

.github/workflows/benchmark.yml

@@ -8,6 +8,9 @@ on:
     paths:
     - '**.swift'
     - '**.yml'
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}-apibreakage
+  cancel-in-progress: true
 
 jobs:
   benchmark-delta:
@@ -88,7 +91,7 @@ jobs:
         with:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           message: ${{ env.PRTEST }}
-          comment_includes: "Pull request benchmark comparison [${{ matrix.os }}] with"
+          comment_tag: benchmark
       - name: Exit with correct status
         run: |
           exit ${{ env.exitStatus }}