Feature/authentication GitHub app

[EinarGaustad]

This pull request introduces support for authenticating with GitHub using a GitHub App, in addition to Personal Access Tokens (PAT), and updates the documentation and code accordingly.

Authentication enhancements:

• Added a new New-GithubAppSession function in githound.ps1 to allow session creation via GitHub App credentials (client ID and private key), including JWT generation and access token retrieval.
• Updated the documentation in README.md to describe both PAT and GitHub App authentication flows, including usage examples and parameter clarifications.

API request improvements:

• Modified the Invoke-GithubRestMethod function in githound.ps1 to use the correct HTTP method ($Method) for paginated requests, instead of always using GET.

Testing

Run the following to obtain a valid session for a GitHub App: $session = New-GithubAppSession -OrganizationName <Name of your Organization> -ClientId (Get-Clipboard) -PrivateKeyPath <Path to Private Key Pem>

[jaredcatkinson]

Thank you for this! I will get testing and get back to you shortly!

[tr4l]

Very nice.
The app token is valid for one hour (if I'm correct).
Did you encounter issue on your scan?