[CI] auto-cancel in-progress PR CI when new commits are pushed (#956)

.github/workflows/amd_ci.yml

 name: CI Test on AMD
 on: [pull_request]
 
+concurrency:
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 env:
   PYTHON_VERSION: '3.12'
   VENV_DIR: tilelang_ci

.github/workflows/ci.yml

 name: CI
 on: [pull_request]
 
+concurrency:
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 env:
   PYTHON_VERSION: '3.12'
   VENV_DIR: tilelang_ci

.github/workflows/metal_ci.yml

 name: CI Test on Metal
 on: [pull_request]
 
+concurrency:
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 env:
   PYTHON_VERSION: '3.12'
   VENV_DIR: tilelang_ci

.github/workflows/publish_docs.yml

@@ -41,4 +41,3 @@ jobs:
           else
             echo "No changes detected, skipping commit and push."
           fi
-