Bump certifi from 2026.2.25 to 2026.5.20

Bumps [certifi](https://github.com/certifi/python-certifi) from 2026.2.25 to 2026.5.20.
- [Commits](certifi/python-certifi@2026.02.25...2026.05.20)

---
updated-dependencies:
- dependency-name: certifi
  dependency-version: 2026.5.20
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]