cancel old matrix tests in CI build

Author: habdelra

.github/workflows/ci.yaml

@@ -99,6 +99,9 @@ jobs:
       matrix:
         shardIndex: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
         shardTotal: [12]
+    concurrency:
+      group: matrix-client-test-${{ matrix.shardIndex }}-${{ github.head_ref || github.run_id }}
+      cancel-in-progress: true
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/init