Release 0.6.3

[rustaceanrob]

Pending feedback from @randomlogin on the LDK side

Steps

• Update the Kyoto version contained in the User Agent of the P2P Version message.
• Update the changelog with the recent commit history.
• Check the documentation for errors using cargo +nightly doc --open
• Increase the version number in Cargo.toml according to semver
• Attempt a publish dry-run using cargo publish --dry-run
• Create a pull request and ensure all tests pass
• Merge the pull request and publish from master

[randomlogin]

Tested locally the new version.
I confirm that it works and simplifies the code for the kyoto chain source of ldk-node.

[rustaceanrob]

0.6.3 is released: https://crates.io/crates/bip157