Support 'optional' fields in proto3

[mingrammer]

Since protoc@v3.15.0, it started to support optional field. It would be nice if the protoc-gen-ts plugin supports it. Could you please work on it? Thanks.

Here is the reference about how to implement.

[LeeStephen]

This would be greatly appreciated.

[isbang]

+1

[huan]

I would love to have this beautiful new feature, now it's a blocker in my project wechaty/grpc#109

[wespen]

+1

[firelizzard18]

I've opened #97 to solve this. If you want to use my repo directly:

% yarn add -D firelizzard18/grpc_tools_node_protoc_ts#feature/proto3-optional

or

% npm install -D firelizzard18/grpc_tools_node_protoc_ts#feature/proto3-optional

[agreatfool]

@firelizzard18 cool, will check in weekend, thanks

[antonphilin]

+1

[agreatfool]

v5.2.0 released