Update dependency pdm-backend to v2.4.1 (#295)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [pdm-backend](https://github.com/pdm-project/pdm-backend) |
build-system.requires | minor | `==2.3.3` -> `==2.4.1` |

---

### Release Notes

<details>
<summary>pdm-project/pdm-backend (pdm-backend)</summary>

###
[`v2.4.1`](https://github.com/pdm-project/pdm-backend/releases/tag/2.4.1)

[Compare
Source](https://github.com/pdm-project/pdm-backend/compare/2.4.0...2.4.1)

#####    🐞 Bug Fixes

- Can't format requirements when converting to setup.py  -  by
[@&#8203;frostming](https://github.com/frostming)
[<samp>(856d8)</samp>](https://github.com/pdm-project/pdm-backend/commit/856d849)
- Update to pyproject_metadata 0.9.0b4  -  by
[@&#8203;frostming](https://github.com/frostming)
[<samp>(88c3f)</samp>](https://github.com/pdm-project/pdm-backend/commit/88c3f44)

#####     [View changes on
GitHub](https://github.com/pdm-project/pdm-backend/compare/2.4.0...2.4.1)

###
[`v2.4.0`](https://github.com/pdm-project/pdm-backend/releases/tag/2.4.0)

[Compare
Source](https://github.com/pdm-project/pdm-backend/compare/2.3.3...2.4.0)

#####    🚀 Features

- Accept context as the second argument to version_format function  - 
by [@&#8203;frostming](https://github.com/frostming) in
[https://github.com/pdm-project/pdm-backend/issues/258](https://github.com/pdm-project/pdm-backend/issues/258)
[<samp>(708aa)</samp>](https://github.com/pdm-project/pdm-backend/commit/708aa3f)
- Update pyproject-metadata to support latest version of PEP 639  -  by
[@&#8203;frostming](https://github.com/frostming) in
[https://github.com/pdm-project/pdm-backend/issues/259](https://github.com/pdm-project/pdm-backend/issues/259)
[<samp>(6c48d)</samp>](https://github.com/pdm-project/pdm-backend/commit/6c48d72)

#####    🐞 Bug Fixes

- Project license field  -  by
[@&#8203;frostming](https://github.com/frostming)
[<samp>(6853a)</samp>](https://github.com/pdm-project/pdm-backend/commit/6853a13)

#####     [View changes on
GitHub](https://github.com/pdm-project/pdm-backend/compare/2.3.3...2.4.0)

</details>

---

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pyproject.toml

@@ -147,5 +147,5 @@ known-first-party = ["mex", "tests"]
 convention = "google"
 
 [build-system]
-requires = ["pdm-backend==2.3.3"]
+requires = ["pdm-backend==2.4.1"]
 build-backend = "pdm.backend"