Cancel workflow for concurrent workflow runs (#69)

Author: rmalmain

.github/workflows/build_and_test.yaml

@@ -6,6 +6,13 @@ on:
   pull_request:
     branches: [ main ]
 
+env:
+  CARGO_TERM_COLOR: always
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: [self-hosted, qemu]