build(deps): bump crypto-bigint from 0.6.0-rc.2 to 0.6.0-rc.4

Bumps [crypto-bigint](https://github.com/RustCrypto/crypto-bigint) from 0.6.0-rc.2 to 0.6.0-rc.4.
- [Changelog](https://github.com/RustCrypto/crypto-bigint/blob/master/CHANGELOG.md)
- [Commits](RustCrypto/crypto-bigint@v0.6.0-rc.2...crypto-bigint/v0.6.0-rc.4)

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

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

elliptic-curve/Cargo.toml

@@ -18,7 +18,7 @@ rust-version = "1.73"
 
 [dependencies]
 base16ct = "0.2"
-crypto-bigint = { version = "0.6.0-rc.2", default-features = false, features = ["rand_core", "hybrid-array", "zeroize"] }
+crypto-bigint = { version = "0.6.0-rc.4", default-features = false, features = ["rand_core", "hybrid-array", "zeroize"] }
 hybrid-array = { version = "0.2.0-rc.8", default-features = false, features = ["zeroize"] }
 rand_core = { version = "0.6.4", default-features = false }
 subtle = { version = "2.6", default-features = false }