v4.0.5
https://github.com/juju/utils/pull/343 Merge v3 branch. https://github.com/juju/utils/pull/341 [from wallyworld/update-go-cleanups](https://github.com/juju/utils/commit/be8e20c97bcc9f4f2bcad4654ef8d9e1df30a5a5) https://github.com/juju/utils/pull/342 [from wallyworld/revert-some-deps](https://github.com/juju/utils/commit/3d7a062e8511e41c6530947248febeae28e3cd90)