Update dependency flake8 to v7.1.1 (#108)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [flake8](https://togithub.com/pycqa/flake8)
([changelog](https://flake8.pycqa.org/en/latest/release-notes/index.html))
| `==7.0.0` -> `==7.1.1` |
[![age](https://developer.mend.io/api/mc/badges/age/pypi/flake8/7.1.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![adoption](https://developer.mend.io/api/mc/badges/adoption/pypi/flake8/7.1.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![passing](https://developer.mend.io/api/mc/badges/compatibility/pypi/flake8/7.0.0/7.1.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/flake8/7.0.0/7.1.1?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

---

### Release Notes

<details>
<summary>pycqa/flake8 (flake8)</summary>

### [`v7.1.1`](https://togithub.com/pycqa/flake8/compare/7.1.0...7.1.1)

[Compare
Source](https://togithub.com/pycqa/flake8/compare/7.1.0...7.1.1)

### [`v7.1.0`](https://togithub.com/pycqa/flake8/compare/7.0.0...7.1.0)

[Compare
Source](https://togithub.com/pycqa/flake8/compare/7.0.0...7.1.0)

</details>

---

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2023_PyData_Berlin/requirements.txt

@@ -2,5 +2,5 @@ numpy==2.1.1
 pandas==2.2.3
 matplotlib==3.9.2
 pytest==8.3.3
-flake8==7.0.0
+flake8==7.1.1
 black==24.8.0