experiment with concurrency

Author: kamilsk

.github/workflows/test.yml

@@ -6,6 +6,10 @@ on: # rebuild any PRs and main branch changes
       - master
       - "releases/*"
 
+concurrency: 
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build: # make sure build/ci work properly
     runs-on: ubuntu-latest