Please add go module support

[roopakv]

This tool is installable via brew. Please add go module support in order to make maintenance easy and support go 1.17

Homebrew/homebrew-core#71289

[bbrks]

It's something we're looking at doing eventually. But we have a lot of non-Go build processes inside Couchbase using the repo/manifest that we need to make sure are lined up for building Sync Gateway with modules first.

[bbrks]

Tracking via CBG-1851

[bbrks]

@roopakv Sync Gateway 3.0.0 and later are now built using Go modules