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 

 Set the new runtime code.

 # <weight>
 - `O(C + S)` where `C` length of `code` and `S` complexity of `can_set_code`
 - 1 storage write (codec `O(C)`).
 - 1 call to `can_set_code`: `O(S)` (calls `sp_io::misc::runtime_version` which is expensive).
 - 1 event.
 The weight of this function is dependent on the runtime, but generally this is very expensive.
 We will treat this as a full block.
 # </weight>

- There are some important upgrades that need to be done for Polkassembly.
- The upgrades will help fix some issues and make Polkassembly work better.
- The upgrades include preventing leaking fd-handlers, adding graceful shutdown for the task manager, and updating libp2p.
- You can find more information about the upgrades on this website: https://github.com/paritytech/polkadot/releases/tag/v0.8.19
- It is recommended to do these upgrades in a timely manner.

#75 SetCode, Kusama runtime 2019