ci: cancel previous workflow run on new commit (#7619)

.github/workflows/gen_json.yml

@@ -3,6 +3,12 @@ on:
   push:
   pull_request:
 
+# https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions#concurrency
+# Ensure that only one commit will be running tests at a time on each PR
+concurrency:
+  group: ${{ github.ref }}-${{ github.workflow }} 
+  cancel-in-progress: true
+
 jobs:
   test_api_json:
     if: github.repository == 'lvgl/lvgl'