*: add proto3 optional support

[glerchundi]

I think it would be good to start thinking on how to add support to the proto3 optional keyword.

This feature request could be addressed in two different steps:

• Add the required supported features parameter to the code generator response go.mod: bump protoc-gen-star to v0.5.3 #432
• Implement optional support in the library

WDYT?

[ivanovishado]

Just in case someone else also stumbled upon this issue: https://stackoverflow.com/a/46821842/4521547

[akonradi]

This sounds good, but we'll need to add optional support to PGS. Blocked on lyft/protoc-gen-star/pull/85

[snqk]

Looks like this can go ahead now. 🎉

[glerchundi]

Checklist updated with the PR bumping to the newly released protoc-gen-star version.

[snqk]

I assume for this, the templates need to be updated for sure, but are there any additional checks that would need to be added?

[nikoncode]

This issue is about support for go or for java too?

[bunch-helen]

I am waiting for this support for Java

[eroshiva]

Hi all,
What is the status of this issue? Is someone working on it? When we should expect a fix for this issue?