gha: add concurrency check

add concurrency check in our workflows to ensure that only a single workflow
using the same concurrency group will run at a time.

more info: https://docs.github.com/en/actions/using-jobs/using-concurrency

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Author: thaJeztah

.github/workflows/test.yml

@@ -10,6 +10,11 @@ permissions:
   contents: read
 
 on: [push, pull_request]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   test:
     strategy: