Bump @apollo/client npm version to 3.0.0-rc.2.

Deliberately putting as little as possible into this release, so that we
can validate the impact of these specific changes (PR apollographql#6395).

Bump @apollo/client npm version to 3.0.0-rc.1.

Bump @apollo/client npm version to 3.0.0-rc.0.

Bump @apollo/client npm version to 3.0.0-beta.54.

Bump @apollo/client npm version to 3.0.0-beta.53.

Bump @apollo/client npm version to 3.0.0-beta.52.

Bump @apollo/client npm version to 3.0.0-beta.51.

Bump @apollo/client npm version to 3.0.0-beta.50.

Bump @apollo/client npm version to 3.0.0-beta.49.