Update dependency pdm to v2.18.1 (#147)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [pdm](https://redirect.github.com/pdm-project/pdm)
([changelog](https://pdm-project.org/latest/dev/changelog/)) | minor |
`==2.17.3` -> `==2.18.1` |

---

### Release Notes

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

###
[`v2.18.1`](https://redirect.github.com/pdm-project/pdm/blob/HEAD/CHANGELOG.md#Release-v2181-2024-08-16)

[Compare
Source](https://redirect.github.com/pdm-project/pdm/compare/2.18.0...2.18.1)

##### Bug Fixes

- Skip checking `project.name` if it is absent when running `pdm
outdated`.
([#&#8203;3095](https://redirect.github.com/pdm-project/pdm/issues/3095))
- Don't remove the `cross_platform` strategy from old lock files.
([#&#8203;3105](https://redirect.github.com/pdm-project/pdm/issues/3105))
- Fix a bug that the VCS revision is lost if the candidate metadata is
cached during resolution.
([#&#8203;3107](https://redirect.github.com/pdm-project/pdm/issues/3107))
- Fix a bug that PDM can't delete source password when saved in keyring.
([#&#8203;3108](https://redirect.github.com/pdm-project/pdm/issues/3108))

###
[`v2.18.0`](https://redirect.github.com/pdm-project/pdm/blob/HEAD/CHANGELOG.md#Release-v2180-2024-08-14)

[Compare
Source](https://redirect.github.com/pdm-project/pdm/compare/2.17.3...2.18.0)

##### Features & Improvements

- Respect certificates in env vars `REQUESTS_CA_BUNDLE` and
`CURL_CA_BUNDLE` when verifying SSL certificates.
([#&#8203;3076](https://redirect.github.com/pdm-project/pdm/issues/3076))
- Allow pypi.verify_ssl to be configured via PDM_PYPI_VERIFY_SSL
environmental variable.
([#&#8203;3081](https://redirect.github.com/pdm-project/pdm/issues/3081))
- Clean logs older than 7 days.
([#&#8203;3091](https://redirect.github.com/pdm-project/pdm/issues/3091))
- Polish the UI looking of locking packages to display the progress.
([#&#8203;3100](https://redirect.github.com/pdm-project/pdm/issues/3100))

##### Bug Fixes

- Fixed `pdm venv activate` to remove quotes such that `iex (pdm venv
activate)` works correctly
([#&#8203;2895](https://redirect.github.com/pdm-project/pdm/issues/2895))
- Don't crash if the version can't be resolved from the self project.
([#&#8203;3077](https://redirect.github.com/pdm-project/pdm/issues/3077))
- Don't fail `install-pdm.py` if there is an invalid `pyproject.toml`
file under the current directory.
([#&#8203;3085](https://redirect.github.com/pdm-project/pdm/issues/3085))
- Make it able to expand env vars in the the dotenv file. Expose
`PDM_PROJECT_ROOT` to the dotenv file for expansion.
([#&#8203;3087](https://redirect.github.com/pdm-project/pdm/issues/3087))
- Fix a bug that Python markers from the existing locked packages are
considered when locking with `--append` option.
([#&#8203;3089](https://redirect.github.com/pdm-project/pdm/issues/3089))
- Backfill urls from configured indexed when exporting to
requirements.txt.
([#&#8203;3094](https://redirect.github.com/pdm-project/pdm/issues/3094))
- Consider the auto-selected Python range when installing from
requirements.txt.
([#&#8203;3095](https://redirect.github.com/pdm-project/pdm/issues/3095))
- Fix a bug that env vars do not override project config correctly.
([#&#8203;3099](https://redirect.github.com/pdm-project/pdm/issues/3099))

</details>

---

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requirements.txt

@@ -1,5 +1,5 @@
 cruft==2.15.0
 mex-release @ git+https://github.com/robert-koch-institut/mex-release.git
-pdm==2.17.3
+pdm==2.18.1
 pre-commit==3.8.0
 wheel==0.44.0