fix: opt module

[khorevaa]

When use -go_out=. --go_opt=module=github.com/khorevaa/awesomeProject2 files not found

Add read option module for --gotag_opt=module=github.com/khorevaa/awesomeProject2 and trim prefix from filename

[srikrsna]

Hi thank you for the PR. Let me check and get back to you. My understanding was that protoc-gen-star takes care of this nuances. But I guess not!

[alexandrevilain]

Hi @srikrsna :)

I can confirm that @khorevaa's PR fixes the opt module. I had the issue using the module option.
@khorevaa's fix makes it work as expected.