Update Readme.md to remove ambiguity for personal token creation

[DhruvAwasthi]

There has been recent change in the ways to create GitHub API token. Earlier there was only one option to create token but now with the recent change one more option is added i.e. Generate new token (Fine-grained, repo-scoped). The current documentation assumes we are creating a token with earlier option i.e. Generate new token (For general use) and thus says "You'll need a GitHub API Token with repo and user scope...". With the advent of new option this is invalid. Hence we need to specify in the Readme.md file to create the token using previous option only. This commit updates that.

[pseusys]

Can't new tokens be used for action running?

[DhruvAwasthi]

@pseusys Ofcourse new tokens can be used as well. But they are more fine-grained and we need some additional steps to give them the same permissions as we need to do with the current ones. Giving permission with current ones is as easy as just doing a check box on two permissions but adding permission on new tokens is a bit complicated.
So there are two way - either we mention to go with the usual one or add documentation on how to give permissions on new tokens.

[pseusys]

I would suggest updating documentation to cover every possibility, especially the newest features.

[DhruvAwasthi]

Makes sense. I will update the PR with the proposed changes.