Bump derive_more from 0.99.7 to 0.99.8 (#146)

Bumps [derive_more](https://github.com/JelteF/derive_more) from 0.99.7 to 0.99.8.
- [Release notes](https://github.com/JelteF/derive_more/releases)
- [Changelog](https://github.com/JelteF/derive_more/blob/master/CHANGELOG.md)
- [Commits](https://github.com/JelteF/derive_more/compare/v0.99.7...v0.99.8)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

bridges/relays/substrate/Cargo.toml

@@ -8,7 +8,7 @@ edition = "2018"
 async-std = "=1.5.0"
 clap = "2.33.1"
 ctrlc = "3.1.4"
-derive_more = "0.99.7"
+derive_more = "0.99.8"
 env_logger = "0.7.1"
 futures = "0.3.5"
 jsonrpsee = { git = "https://github.com/paritytech/jsonrpsee", features = ["ws"] }