Labels: The labels associated with this Project. Label keys must be between 1 and 63 characters long and must conform to the following regular expression: \[a-z\](\[-a-z0-9\]*\[a-z0-9\])?. Label values must be between 0 and 63 characters long and must conform to the regular expression (\[a-z\](\[-a-z0-9\]*\[a-z0-9\])?)?. No more than 256 labels can be associated with a given resource. Clients should store labels in a representation such as JSON that does not depend on specific characters being disallowed. Example: "environment" : "dev" Read-write.