Release v1.6.1

Docker reference: paritytech/substrate-relay:v1.6.1

Rococo: 1_010_000;
Westend: 1_010_000;
Kusama: 1_002_004;
Polkadot: 1_002_000;
Rococo Bridge Hub: 1_010_000;
Westend Bridge Hub: 1_010_000;
Kusama Bridge Hub: 1_002_004;
Polkadot Bridge Hub: 1_002_002;
Rococo Bulletin: not supported yet;
Polkadot Bulletin: not supported yet.

What's Changed

• Support subcommand to relay messages delivery confirmation by @svyatonik in #2989
• Relay v1.6.1: added support for bridge-hub-kusama/1002004 + aligned kusama/1002004, P to polkadot/1002000 by @bkontur in #3007

Full Changelog: v1.6.0...v1.6.1