Update thiserror requirement from 1.0.40 to 2.0.3 in /rust (#251)

Updates the requirements on [thiserror](https://github.com/dtolnay/thiserror) to permit the latest version.
- [Release notes](https://github.com/dtolnay/thiserror/releases)
- [Commits](dtolnay/thiserror@1.0.40...2.0.3)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

rust/Cargo.toml

@@ -10,7 +10,7 @@ homepage = "https://roualdes.github.io/bridgestan/latest/"
 
 [dependencies]
 libloading = "0.8.0"
-thiserror = "1.0.40"
+thiserror = "2.0.3"
 path-absolutize = { version = "3.1" }
 log = { version = "0.4" }
 ureq = { version = "2.7", optional = true }