Release v21.5.0

Changed

• QueryFor.perform resolves with an unsuccessful result when the request never reaches the server, instead of rejecting (#2473)
• A query that fails in transport now surfaces through useSuspenseQuery's error boundary as QueryFailed, where it previously left the boundary pending forever (#2473)
• Only a successful query result is cached, so a failed attempt no longer seeds a later mount of the same query (#2473)

Fixed

• useQuery settles as unsuccessful when a query fails in transport, carrying the exception message, instead of reporting that it is still performing forever (#2473)
• An aborted, superseded query request can no longer settle over the newer request that replaced it (#2473)
• CommandForm no longer lets an initialValues key holding undefined overwrite a value that currentValues resolved (#2493)