support rawquery in ssh (scp) transport

[isaaguilar]

Hi Will, not sure the policy on PRs but I made some tweaks to accept RawQuery strings for the ssh transport. Hope this can help someone.

Before the update, this code did not produce a RawQuery output:

func main() {
	a, _ := giturls.Parse("[email protected]:org/repo.git?ref=abc/123")
	fmt.Println(a, "query:", a.RawQuery)
}

Results before this PR:

$ go run main.go
ssh://[email protected]/org/repo.git%3Fref=abc/123 query:

Results with changes in the PR:

$ go run main.go
ssh://[email protected]/org/repo.git?ref=abc/123 query: ref=abc/123

Cheers!

[whilp]

Awesome -- LGTM.

[whilp]

Thanks for adding the go.mod as well!