upgrade to v0.9.42

[bernardoaraujor]

Motivation

Substrate/Polkadot v0.9.37/38/39 has demonstrated instabilities for parachains.

e.g.:

• Rococo collator running on aws eks fails and restart every few minutes paritytech/polkadot-sdk#642
• V5.3.0 version node log error: [Relaychain] error=Subsystem(Generated(Context("Signal channel is terminated and empty."))) AstarNetwork/Astar#910

Suggested Solution

We should have a polkadot-v0.9.42 branch available.

[koushiro]

related PR: paritytech/polkadot#1054

[bernardoaraujor]

as a temporary workaround to unblock https://github.com/paritytech/mythical-node/issues/26 while paritytech/polkadot#1054 isn't merged, I ported the work from koushiro:update-polkadot-v0.9.42 into bar/polkadot-v0.9.42

the only difference is that it is structured similarly to a release branch, so all substrate and polkadot dependencies point to *-v0.9.42 instead of `master.

[koushiro]

@bernardoaraujor Just curious, what's this repo (https://github.com/paritytech/mythical-node) being used for? 👀

[bernardoaraujor]

it's a project for a Parity client