v2.2.0 cannot be used with Go modules

[F21]

Although there is a go.mod file in the repository, the latest version that can be used with Go modules (unless we force it to use a commit) is v2.1.1. This is because the tag is v2.2.0, but the import path is still github.com/cenkalti/backoff.

With go modules, once you get to v2 and up, you need to update the import path to github.com/cenkalti/backoff/v2 and so on.

[cenkalti]

I believe it is fixed now. I have followed the instructions here: https://github.com/golang/go/wiki/Modules#releasing-modules-v2-or-higher

I have bumped the version to v3.0.0 and set v3 as main branch for the project.

[cenkalti]

@F21 Can you confirm please?

[F21]

@cenkalti Thanks for getting this sorted! This should fix the issue 👍

[bcmills]

Note that the v3 release doesn't fix users on the non-/v3 import path. You may want to branch and tag a v2.2.1 release that is the same as v2.2.0 but without the go.mod file.

[cenkalti]

@bcmills Done.