When using the GitHub plugin subscribe functionality, if the repo name does not match the case it creates an invalid subscription.
For example, with the repo "DHaussermann/hello-world" subscribe by typing "/github subscribe dhaussermann/hello-world" where the D and H in the owner name are lower case.
The response from the plugin is that the subscription was successful. No events will ever get delivered from the repo.
We should prevent user error by either making this case insensitive or telling the user the repo is unknown and not creating the subscription.
This is not a new issue. It has existed for a long time.