Bump num-bigint from 0.2.5 to 0.2.6

Bumps [num-bigint](https://github.com/rust-num/num-bigint) from 0.2.5 to 0.2.6.
- [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-0.2.5...num-bigint-0.2.6)

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

Cargo.lock

@@ -453,9 +453,9 @@ dependencies = [
 
 [[package]]
 name = "num-bigint"
-version = "0.2.5"
+version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6f115de20ad793e857f76da2563ff4a09fbcfd6fe93cca0c5d996ab5f3ee38d"
+checksum = "090c7f9998ee0ff65aa5b723e4009f7b217707f1fb5ea551329cc4d6231fb304"
 dependencies = [
  "autocfg 1.0.0",
  "num-integer",