It's not possible to install with go install

[jsravn]

❯ go install github.com/sky-uk/osprey@v2.7.0
go install: github.com/sky-uk/osprey@v2.7.0: github.com/sky-uk/osprey@v2.7.0: invalid version: module contains a go.mod file, so major version must be compatible: should be v0 or v1, not v2

And go install of @latest picks up the old v1.5.0 version, which panics when running.

go install github.com/sky-uk/osprey@latest
go: downloading github.com/sky-uk/osprey v1.5.0
...
osprey user login
panic: mismatching message name: got pb.LoginResponse, want pb.ConsumeLoginResponse

Also see #45

[saley89]

Linked draft PR which we think may resolve this issue. Needs additional work to test it out and ensure it is indeed the fix.

Resulted from this doc: https://github.com/golang/go/wiki/Modules#semantic-import-versioning