Prepare for 2.2.0.
[maven-release-plugin] prepare release protoparser-2.2.0
[maven-release-plugin] prepare for next development iteration
Add support for values as lists

Example:

service SearchService {
  rpc Purchase (PurchaseRequest) returns (PurchaseResponse) {
    option (squareup.a.b) = { value: [FOO, BAR] };
  }
}
Add constructors to ProtoSchemaParser that accept a Reader or an InputStream