Remove `gh-extension` topic from this repository

[mislav]

Hi, thanks for maintaining a list of awesome CLI extensions.

GitHub CLI searches repositories with the gh-extension topic to programmatically discover installable extensions. Your repository has that topic, but it isn't an extension one can install. It would be helpful if you removed the misleading topic, since that would make gh extension search command more efficient. Thank you!

[lakuapik]

@mislav removed, thanks.