Update gpt requirement from 3.1.0 to 4.0.0

Updates the requirements on [gpt](https://github.com/Quyzi/gpt) to permit the latest version.
- [Release notes](https://github.com/Quyzi/gpt/releases)
- [Changelog](https://github.com/Quyzi/gpt/blob/master/CHANGELOG.md)
- [Commits](Quyzi/gpt@v3.1.0...v4.0.0)

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

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

Cargo.toml

@@ -11,7 +11,7 @@ authors = ["Stefan Rabmund <[email protected]>"]
 readme = "crates-io.md"
 
 [dependencies]
-gpt = {version = "3.1.0", optional=true}
+gpt = {version = "4.0.0", optional=true}
 thiserror = "1.0"
 
 [dev-dependencies]