Bump num-bigint from 0.4.1 to 0.4.2

Bumps [num-bigint](https://github.com/rust-num/num-bigint) from 0.4.1 to 0.4.2.
- [Release notes](https://github.com/rust-num/num-bigint/releases)
- [Changelog](https://github.com/rust-num/num-bigint/blob/master/RELEASES.md)
- [Commits](https://github.com/rust-num/num-bigint/compare/num-bigint-0.4.1...num-bigint-0.4.2)

---
updated-dependencies:
- dependency-name: num-bigint
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Cargo.toml

@@ -30,7 +30,7 @@ serde_json = "1.0.67"
 bincode = "1.3.3"
 serde_cbor = "0.11.2"
 base64 = "0.13.0"
-num-bigint = "0.4.1"
+num-bigint = "0.4.2"
 num-traits = "0.2.14"
 chrono = { version = "0.4.19", features = ["serde"] }
 rand = { version = "0.8.4", package = "rand" }