Bump regex from 1.3.9 to 1.4.0 in /blacksmith

Bumps [regex](https://github.com/rust-lang/regex) from 1.3.9 to 1.4.0.
- [Release notes](https://github.com/rust-lang/regex/releases)
- [Changelog](https://github.com/rust-lang/regex/blob/master/CHANGELOG.md)
- [Commits](rust-lang/regex@1.3.9...1.4.0)

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

Author: dependabot-preview[bot]

blacksmith/Cargo.lock

@@ -10,7 +10,7 @@ publish = false
 [dependencies]
 env_logger = "0.7.1"
 log = "0.4.11"
-regex = "1.3.9"
+regex = "1.4.0"
 reqwest = { version = "0.10", features = ["blocking"] }
 serde = { version = "1.0.116", features = ["derive"] }
 serde_json = "1.0.58"