Add a timeout and a concurrency group to the json_view benchmarks

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

.github/workflows/json_view_benchmarks.yml

@@ -39,6 +39,11 @@ on:
 permissions:
   contents: read
 
+concurrency:
+  # (the label is part of the group: adding an unrelated label must not cancel a running benchmark)
+  group: json-view-benchmarks-${{ github.workflow }}-${{ github.ref }}-${{ github.event.label.name }}
+  cancel-in-progress: true
+
 jobs:
   compare:
     if: github.event_name == 'workflow_dispatch' || github.event.label.name == 'benchmark'
@@ -46,6 +51,7 @@ jobs:
       matrix:
         runner: ${{ fromJSON(github.event_name == 'workflow_dispatch' && format('["{0}"]', inputs.runner) || '["ubuntu-24.04", "ubuntu-24.04-arm"]') }}
     runs-on: ${{ matrix.runner }}
+    timeout-minutes: 60
     steps:
       - name: Harden Runner
         uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1