add license checker to CI

.github/workflows/license-checker.yml

@@ -0,0 +1,20 @@
+name: License checker
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  check-license:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Check License Header
+        uses: apache/skywalking-eyes@main
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.licenserc.yaml

@@ -0,0 +1,30 @@
+header:
+  license:
+    spdx-id: Apache-2.0
+    copyright-owner: PingCAP, Inc.
+  paths-ignore:
+    - 'docs/'
+    - 'br/'
+    - '.gitignore'
+    - '.gitattributes'
+    - '.golangci.yml'
+    - '.licenserc.yaml'
+    - 'LICENSES/'
+    - '**/*.md'
+    - '**/*.json'
+    - '**/*.pem'
+    - '**/*.crt'
+    - '**/*.test'
+    - '**/*.result'
+    - '**/*.example'
+    - '.codecov.yml'
+    - 'circle.yml'
+    - 'errors.toml'
+    - 'Jenkinsfile'
+    - '.editorconfig'
+    - 'hooks/pre-commit'
+    - '**/go.mod'
+    - '**/go.sum'
+    - 'LICENSE'
+    - '.github/'
+  comment: on-failure