[Need Help] How can I generate Swagger/OpenAPI v3 spec from .proto files and vice versa

It seems that only binary protocol buffers are supported for interconversion between protobuf and swagger. How can I convert binary protocol buffers (`.pb`) to and from proto3 protocol buffers (`.proto`), is that even a sane question to ask.

Moreover, my final intent is to be able to interconvert between `.proto` and OpenAPI2/3 spec (`.json/.yaml`) files, either using annotations in the `.proto` file, some tags or otherwise.

Thanks in advance!

### Edits:
Modifying the issue title a little to highlight the use case much better.

### External links:
[Stack Overflow | How to generate swagger3 (OpenAPI3) spec in (.json/.yaml) from protobuf (.proto) files?](https://stackoverflow.com/questions/61350097/how-to-generate-swagger3-openapi3-spec-in-json-yaml-from-protobuf-proto)