github-card | GitHub profile search using Reactjs | User Interface library

I am working on a project that is using Octokit to return data from the Github API. It is returning a 401 Bad Credentials and I am unsure of how to debug the problem.

In the documentation it says to separate the private key lines with '\n' and paste it all in the same line in the code. Because I don't want to store the private key in the code I am loading in the key from a separate .pem file using fs.readFileSync(githubCert).toString(). Is this the correct way to load the private key?

I have tried recreating my .pem file, including it in the code in the way described by the documentation (Also explained above) and tried using 'token' instead of 'bearer' (I know this shouldn't work but it was worth a shot).

My questions are is this the correct way of doing it? And what would be the proper process to debugging this kind of error?

Heres my code:

I am creating a Octokit app and getting the JWT token using: