Add version constructor

[kazhuravlev]

This New function is helpful for code like that

versions := []string{
  "v0.1.0",
  "v0.4.0",
}

maxVersion := semver.New(0, 0, 0, "", "")
for _, version := range versions{
  v, _ := semver.NewVersion(version)
  if v.GreaterThan(maxVersion) {
    maxVersion = v
  }
}

fmt.Println(maxVersion)

[kazhuravlev]

@mattfarina I merge origin to my PR. Workflow green now. Please, re-run the workflow in this PR.

[mattfarina]

I added a test for the New function and merged. Will be in the next release.