build(deps): update rand_regex requirement from 0.15 to 0.16

Updates the requirements on [rand_regex](https://github.com/kennytm/rand_regex) to permit the latest version.
- [Release notes](https://github.com/kennytm/rand_regex/releases)
- [Changelog](https://github.com/kennytm/rand_regex/blob/master/CHANGELOG.md)
- [Commits](kennytm/rand_regex@v0.15.0...v0.16.0)

---
updated-dependencies:
- dependency-name: rand_regex
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

lib/Cargo.toml

@@ -43,7 +43,7 @@ jsonwebtoken = { version = "8.1", default-features = false }
 rand_xorshift = "0.3"
 rand = "0.8"
 regex-syntax = { version = "0.6", default-features = false }
-rand_regex = { version = "0.15", default-features = false }
+rand_regex = { version = "0.16", default-features = false }
 thiserror = "1.0"
 rand_distr = "0.4"