Adds support for skipping tools.go

[jcchavezs]

Currently files like tools.go or or including // +build tools should be skipped.

[jcchavezs]

Actually we should be able to skip specific +build tags instead of arbitrary support tools only.

[jcchavezs]

I'd really like to hear your feedback on this one @mx-psi

[mx-psi]

Having the ability to filter by build tags sounds like a good idea, but I am not sure what is the best default for this: I don't love golangci-lint default behavior of excluding everything (e.g. I feel like build tags like windows should be included by default)

[jcchavezs]

I think in this case we should do denylist instead of allowlist. Maybe not the most popular choice but in general you only want to exclude from vanity import either autogenerated files or tools in which case ignoring a build tag would do the trick. Remember it is also a common practice adding a build tag for ignoring files as part of the compilation and dependency resolution.