Bump idna from 3.16 to 3.18 (#427)

Bumps [idna](https://github.com/kjd/idna) from 3.16 to 3.18.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.md)
- [Commits](kjd/idna@v3.16...v3.18)

---
updated-dependencies:
- dependency-name: idna
  dependency-version: '3.18'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend/requirements.txt

@@ -17,7 +17,7 @@ djangorestframework-xml==2.0.0
 drf-spectacular==0.29.0
 drf-yasg==1.21.15
 filelock==3.29.0
-idna==3.16
+idna==3.18
 inflection==0.5.1
 iniconfig==2.3.0
 isort==6.1.0