[REQ] Support injecting custom GOPROXY into gomod generator

[cpuguy83]

What kind of request is this?

None

What is your request or suggestion?

We'd like to be able to use a custom GOPROXY in the gomod generator so that it can download mods using our own proxy instead of the default one.
This should be able to use build-args like we do for other injectable values and not require it to appear in the spec file.

Are you willing to submit PRs to contribute to this feature request?

• Yes, I am willing to implement it.