chore: cancel previous workflow runs in progress

Author: mdjastrzebski

.github/workflows/ci.yml

@@ -5,6 +5,10 @@ on:
   pull_request:
     branches: ['**']
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ !contains(github.ref, 'main')}}
+
 jobs:
   install-cache-deps:
     runs-on: ubuntu-latest