Introduce skywalking-eyes to check license headers (#29)

* skywalking-eyes

* Update PROJECT

Co-authored-by: Zhenxu Ke <kezhenxu94@apache.org>
diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index 2f1c139..867a289 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -34,6 +34,10 @@
           id: go
       - name: Check out code into the Go module directory
         uses: actions/checkout@v2
+      - name: Check License
+        uses: apache/skywalking-eyes@main
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       - name: Update dependencies
         run: GOPROXY=https://proxy.golang.org go mod download
       - name: Lint
diff --git a/PROJECT b/PROJECT
index e16efc9..60b7a6e 100644
--- a/PROJECT
+++ b/PROJECT
@@ -1,3 +1,21 @@
+# Licensed to Apache Software Foundation (ASF) under one or more contributor
+# license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright
+# ownership. Apache Software Foundation (ASF) licenses this file to you under
+# the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
 domain: skywalking.apache.org
 multigroup: true
 repo: github.com/apache/skywalking-swck