chore(readme):Update Link to Latest GitHub Personal Access Token Documentation

[vamsi4845]

This PR closes #1904.

This PR updates the link to the GitHub Personal Access Token documentation in README to point to the latest version available for GitHub Enterprise Server 3.13.

Changes:

Updated the link from:
(https://docs.github.com/en/enterprise-server@3.4/authentication/keeping-your-account-and-data-secure/managing-your-personal-access-tokens)

to:
(https://docs.github.com/en/enterprise-server@3.13/authentication/keeping-your-account-and-data-secure/managing-your-personal-access-tokens)

Reason for Change:
The previous link pointed to an outdated version of the documentation. Updating to the latest version ensures that contributors have the most current instructions for creating a GitHub Personal Access Token.

Checklist

• Breaking changes are clearly marked as such in the PR description and changelog

Before requesting review

• I have reviewed the code myself

[CLAassistant]

All committers have signed the CLA.

[xgreenx]

Thank you for your contribution, but the old link still works. Closing this PR for now.