Update package.json "homepage" URL to default react docs (#7885)
Update package.json "homepage" URL to default react docs (#7885)

Previously, the "homepage" link for the @apollo/client npm package took
devs to https://apollographql.com.

Note from @benjamn: Although /docs/react does include documentation
about React APIs, it also covers the rest of the Apollo Client APIs in depth,
so it tends to be the best place for anyone to start.
apollographql/apollo-client,apollographql/apollo-client