Merge pull request #243 from python-desert/cancel_old_pr_runs

cancel old pr runs on new push

Author: altendky

.github/workflows/ci.yml

@@ -8,6 +8,10 @@ on:
       - v*
   pull_request:
 
+concurrency:
+  group: ${{ github.ref }}-${{ github.workflow }}-${{ github.event_name }}-${{ github.ref == format('refs/heads/{0}', github.event.repository.default_branch) && github.sha || '' }}
+  cancel-in-progress: true
+
 jobs:
   ci:
     runs-on: ubuntu-latest