Upgrade priority: Medium (timely upgrade recommended) - due to change(s): Update to latest sysinfo prevents leaking fd-handlers (paritytech/substrate#6708) Graceful shutdown for the task manager (paritytech/substrate#6654) Update libp2p to 0.22. (paritytech/substrate#6690)

Specs of the runtime can be found here: https://github.com/paritytech/polkadot/releases/tag/v0.8.19 

 Schedule a majority-carries referendum to be tabled next once it is legal to schedule
 an external referendum.

 The dispatch of this call must be `ExternalMajorityOrigin`.

 - `proposal_hash`: The preimage hash of the proposal.

 Unlike `external_propose`, blacklisting has no effect on this and it may replace a
 pre-scheduled `external_propose` call.

 # <weight>
 - Complexity: `O(1)`
 - Db write: `NextExternal`
 - Base Weight: 3.065 µs
 # </weight>

- There are some updates that need to be made to the Polkadot system.
- The updates will help prevent leaking fd-handlers and allow for a graceful shutdown of the task manager.
- The libp2p will also be updated to version 0.22.
- The specifications of the runtime can be found at the provided link.
- It is recommended to make these updates in a timely manner.

#184 SetCode, Kusama runtime 2019