Relax lint checks on autogenerated protobuf packages

[tstromberg]

This was raised by a comment from @displague

Off the top of my head, the only linter I can think that this might impact is the gofumpt checker.

[mmlb]

I lean towards not doing this. I'd rather have the go:generate step run goimports/gofumpt. I find it easier to avoid snowflakes.

[displague]

If the make tasks (fmt,fix,gen?) do the right thing, and the contributing guides say as much, I don't think we would need to bog down the Go generator process or reduce the linter levels.