Add update tag to @relation graphql for relationships to make any mutations update the timestamp of the related document

Like with the other variables in the @relation tag, add an update modifier to put on the side of relationsips, or an update boolean for the @relationship tag that will edit other automatically made Create, Update and Delete, functions for different documents to update the timestamp of documents that are grouped.

As an example

type Message {
chatRoom: ChatRoom! @relation(name: “chat_owner”, update: true)
message: String!
}

type ChatRoom {
name: String!
messages: [Message] @relation(name: “chat_owner”, update: true)
}

and this would automatically change the timestamp for any Chat Room document that is connected to a Message document, when the message document is created, updated, or deleted and also connected to that channel document. This is useful for Streaming, as it prevents having to use bodged together code like having to create a UDF for every document where you want something like this to occur for GraphQL mutations.