chore: add license header (#35)

Signed-off-by: Ruihang Xia <waynestxia@gmail.com>

go/greptime/v1/meta/heartbeat.pb.go

@@ -1,3 +1,17 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed 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.
+
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
 // 	protoc-gen-go v1.28.1
@@ -574,7 +588,8 @@ type MailboxMessage struct {
 
 	// The id is used to associate request and response.
 	Id uint64 `protobuf:"varint,1,opt,name=id,proto3" json:"id,omitempty"`
-	// The following information plays a bigger role in making messages traceable and facilitating debugging.
+	// The following information plays a bigger role in making messages traceable
+	// and facilitating debugging.
 	Subject string `protobuf:"bytes,2,opt,name=subject,proto3" json:"subject,omitempty"`
 	From    string `protobuf:"bytes,3,opt,name=from,proto3" json:"from,omitempty"`
 	To      string `protobuf:"bytes,4,opt,name=to,proto3" json:"to,omitempty"`