add checksumBehavior with update value to allow installing dependencies with yarn

[raulmarindev]

By default, Yarn will throw an exception on yarn install if it detects that a package doesn't match the checksum stored within the lockfile. This was the change applied:

1. Open your .yarnrc.yml.
2. Add the following configuration option: checksumBehavior: "update"

[pastelsky]

Closing this as the checksum has now been updated.