don't make the whole PR look red if benchmarks can't post.

Author: kivikakk

.github/workflows/benchmarks.yml

@@ -1,6 +1,6 @@
 name: benchmarks
 
-on: 
+on:
   pull_request:
     types:
       - opened
@@ -33,4 +33,5 @@ jobs:
       - name: Post result comment
         uses: mshick/add-pr-comment@v2
         with:
-          message-path: bench-output.md
+          message-path: bench-output.md
+        continue-on-error: true