文档：graphql文档补充，批量操作

[涂佳俊]

mutation {
  update1:project__update(id:"62620e4d87e5c50032d9bd25", doc:{_id:"62620e4d87e5c50032d9bd25",name:"123"}) {
    _id
    name
  }
  update2:project__update(id:"62620e5787e5c50032d9bd39", doc:{name:"456"}) {
    _id
    name
  }
}