Consider removing "github-pages" environment

[sobolevn]

It is listed as an active deployment: https://github.com/python/typeshed/deployments
But, it does not look that active to me ;)

It is also listed here:

[JelleZijlstra]

I have permission to delete this at https://github.com/python/typeshed/settings/environments (IIRC @srittau has this access too) but I'll wait a little bit in case somebody knows what it's for.

[AlexWaygood]

I'll wait a little bit in case somebody knows what it's for.

If I understand correctly, it was added by mistake :) #7537 (comment)

[JelleZijlstra]

Thanks, that explains what happened. I deleted it now.

[srittau]

Thanks for finding this!