Escape commit ref with percent encoding

[bgpat]

If Repositories.GetCommitSHA1 was called with the branch name which includes non-alphabet character, it occurs an error. It looks to require escaping with percent encoding.

Below is sample code:

package main

import (
	"context"
	"fmt"

	"github.com/google/go-github/github"
)

func main() {
	client := github.NewClient(nil)
	sha1, _, err := client.Repositories.GetCommitSHA1(ctx, "bgpat", "test", "cpu100%", "")
	if err != nil {
		panic(err)
	}
	fmt.Println(sha1)
}

before: parse repos/bgpat/test/commits/cpu100%: invalid URL escape "%"
after: 46736bd30fe65160f7d21e49d8f23e4687abc41b

[gmlewis]

Thank you, @bgpat!
LGTM.
Awaiting second LGTM before merging.

[gmlewis]

I'm curious if there are other APIs in our repo where we have made the same mistake?

I'm betting that anywhere we pass a ref in the URL, we would need to escape it.

While you are here, @bgpat, do you want to take a look?

[bgpat]

I found 9 same mistakes. I will fix it.

$ grep -n Sprintf *.go | grep ', ref\W'
checks.go:258:	u := fmt.Sprintf("repos/%v/%v/commits/%v/check-runs", owner, repo, ref)
checks.go:324:	u := fmt.Sprintf("repos/%v/%v/commits/%v/check-suites", owner, repo, ref)
git_refs.go:60:	u := fmt.Sprintf("repos/%v/%v/git/refs/%v", owner, repo, ref)
git_refs.go:91:	u := fmt.Sprintf("repos/%v/%v/git/refs/%v", owner, repo, ref)
git_refs.go:211:	u := fmt.Sprintf("repos/%v/%v/git/refs/%v", owner, repo, ref)
repos_commits.go:192:	u := fmt.Sprintf("repos/%v/%v/commits/%v", owner, repo, ref)
repos_statuses.go:47:	u := fmt.Sprintf("repos/%v/%v/commits/%v/statuses", owner, repo, ref)
repos_statuses.go:72:	u := fmt.Sprintf("repos/%v/%v/statuses/%v", owner, repo, ref)
repos_statuses.go:111:	u := fmt.Sprintf("repos/%v/%v/commits/%v/status", owner, repo, ref)

[bgpat]

@gmlewis I escaped all ref. Please review.

[gmlewis]

OK, this is true awesomeness... thank you so much, @bgpat!
LGTM.

Awaiting input from @gauntface as a sanity check to make sure my review makes sense... then we will get this in.

[gauntface]

This looks great to me. We should look at adding some tests to make sure we don't regress on this in the future, but that can be done separately.

Thank you for fixing this :)

[gmlewis]

Excellent point, @gauntface!
I've added issue #1101 to track this.
Merging.

[gmlewis]

This is a bug fix. Bumping package version number to capture it.