Add support for protobuf editions

[solidDoWant]

Version bump + 4 line change to add support for protobuf editions up to 2023 (current latest supported by protoc-gen-go). This has no effect on the program output, but without it, protoc will fail with

<proto file name>.proto: is an editions file, but code generator protoc-gen-go-grpcmock hasn't been updated to support editions yet.  Please ask the owner of this code generator to add support or switch back to proto2/proto3.

See https://protobuf.dev/editions/overview/ for more information.

on any proto files that use edition instead of syntax.

[felix-kaestner]

@solidDoWant Thank you for your contribution! Adding support for editions is really appreciated. The only thing I'm a bit skeptical about is specifying a min/max version.

What is the benefit of adding the minimum and maximum supported versions here? To my knowledge we are not making use of any version specific features. Adding a maximum version means that we would have to maintain this from now on and bump it every time a new edition comes out, which I would like to avoid if possible.

[solidDoWant]

Adding a maximum version means that we would have to maintain this from now on and bump it every time a new edition comes out, which I would like to avoid if possible.

Completely get that. Unfortunately I think it's required. I did some local testing and without these set, the generator with a very generic error about unsupported versions. Every other tool with editions support seems to have these set.

I think I found a workaround to solve the issue. protoc-gen-go sets these using constants, which the upstream project updates when new versions release. 58237fb sets the values to these variables, so while they will need to be updated upstream (and a new release cut), the code itself won't need to change.

[felix-kaestner]

Well, that's unfortunate. Though in this scenario, I'd prefer to explicitly define the constants for Min/MaxSupportedVersions (sorry for the back and forth) since I think it would be weird to tie this to a specific protoc-gen-go version. If we have to increment these every time a new edition is released, then I'd prefer it to actually be a code change instead of changing something in the background by just updating the dependencies.

Would you be able to also add a file with editions syntax to the examples? E.g. just taking https://github.com/lovoo/protoc-gen-go-grpcmock/blob/main/examples/helloworld/helloworld.proto and add another version of this file with editions syntax? Just so we can verify that we are able to support it?