docs: update release process github token instructions
and fix the gpg generating key url
## Requirements
- [hub](https://github.com/github/hub)
- * Using an [application token](https://github.com/settings/tokens) is required for hub.
+ * Using an [application token](https://github.com/settings/tokens) is required for hub (set to a GITHUB_TOKEN environment variable).
- GitHub permissions to push tags and create releases in Kata repositories.
-- GPG configured to sign git tags. https://help.github.com/articles/generating-a-new-gpg-key/
+- GPG configured to sign git tags. https://docs.github.com/en/authentication/managing-commit-signature-verification/generating-a-new-gpg-key
- You should configure your GitHub to use your ssh keys (to push to branches). See https://help.github.com/articles/adding-a-new-ssh-key-to-your-github-account/.
* As an alternative, configure hub to push and fork with HTTPS, `git config --global hub.protocol https` (Not tested yet) *
