cmd/ghcs/delete: When matching repos to delete, standardize casing

- It was possible to delete Codespaces for repo `SomePerson/foo` but not
  `someperson/foo`, despite the fact that the GitHub APIs don't actually
  care about casing - `SomePerson` and `someperson` is the same account.
- This fixes that by lowercasing both the user-provided repo name, and
  the repository that is attached to the Codespace for a match.
- Fixes #76.

cmd/ghcs/delete.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"strings"
 
 	"github.com/github/ghcs/api"
 	"github.com/github/ghcs/cmd/ghcs/output"
@@ -124,7 +125,7 @@ func DeleteByRepo(repo string) error {
 
 	var deleted bool
 	for _, c := range codespaces {
-		if c.RepositoryNWO != repo {
+		if strings.ToLower(c.RepositoryNWO) != strings.ToLower(repo) {
 			continue
 		}
 		deleted = true