v2 is good for public API. PBM does not provide stable Golang public API. It's designed as binaries. The only public API is pbm CLI. Any function in the repo can be changed at any time.
So before switching to a v2-like module, we must establish Golang public API that will follow "semver".

Secondly, I do not see a reason to introduce v2 within the ongoing major release. This is better to do at least the next major v3 release.

The recommendation was designed to follow the semantic version or, at least, be API-compatible within a major version. As for now, we cannot guarantee we won't introduce breaking changes in the public function, type, etc. Doing it now will restrict us.

Basically, "github.com/percona/percona-backup-mongodb/*" is semantically private.

also see PBM-780

I see

Private packages are meant to be in internal/ but as mentioned in the Jira "The operator uses internal functions which are not considered public.", which prevents you from doing it.

As a feedback, I found confusing the combination of non-internal/ packages the tagging strategy for binaries colliding with the golang way of publishing package version =!=> the packages can be used. It made me think that those packages are public. Any other tagging convention (to avoid that 1.13 vs 1.14), or a message in the readme, would have prevent me from losing my time. But that might be just me 😉

I let you close the PR

added message to readme about it (#804)