Support case-insensitive in REST API

[whywaita]

Now

https://github.com/octo-org/hello-world-javascript-action

• OK: octo-org/hello-world-javascript-action
• NG: OCTO-ORG/hello-world-javascript-action

Expected

• OK: octo-org/hello-world-javascript-action OCTO-ORG/hello-world-javascript-action