Why is the Approve button disabled in GitHub “pull request review”?

Question

Problem Background:

So far I am the sole owner of a GitHub repo. I committed the code from my system to a branch called release (actually its a tag

Answer 1

If you were the one who has committed the pull request you cannot approve or request changes on this pull request. It's only available when someone else requested such action.

So your only option is to comment it.