build(deps): bump certifi from 2025.4.26 to 2025.6.15

Bumps [certifi](https://github.com/certifi/python-certifi) from 2025.4.26 to 2025.6.15.
- [Commits](certifi/python-certifi@2025.04.26...2025.06.15)

---
updated-dependencies:
- dependency-name: certifi
  dependency-version: 2025.6.15
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -1,5 +1,5 @@
 asgiref==3.8.1
-certifi==2025.4.26
+certifi==2025.6.15
 charset-normalizer==3.4.2
 django-environ==0.12.0
 Django==5.2.3