Ensure generated JSON is always valid.
Ensure generated JSON is always valid.

Since typeURL can be set by the developer, we need to ensure it
doesn't contain something that could make invalid JSON, so always
use a JSONEncoder so the string can be properly escaped.

allevato/swift-protobuf,tbkka/swift-protobuf,apple/swift-protobuf,cburrows/swift-protobuf,apple/swift-protobuf,allevato/swift-protobuf,apple/swift-protobuf,tbkka/swift-protobuf,allevato/swift-protobuf,apple/swift-protobuf,cburrows/swift-protobuf,thomasvl/swift-protobuf,thomasvl/swift-protobuf,tbkka/swift-protobuf,tbkka/swift-protobuf,cburrows/swift-protobuf,apple/swift-protobuf,apple/swift-protobuf,apple/swift-protobuf,thomasvl/swift-protobuf,allevato/swift-protobuf,cburrows/swift-protobuf,allevato/swift-protobuf,tbkka/swift-protobuf,thomasvl/swift-protobuf,thomasvl/swift-protobuf,tbkka/swift-protobuf,cburrows/swift-protobuf,thomasvl/swift-protobuf,allevato/swift-protobuf,cburrows/swift-protobuf,thomasvl/swift-protobuf,tbkka/swift-protobuf,cburrows/swift-protobuf,allevato/swift-protobuf