Bump easy-thumbnails from 2.8.5 to 2.9 (#4247)

Bumps [easy-thumbnails](https://github.com/SmileyChris/easy-thumbnails) from 2.8.5 to 2.9.
- [Release notes](https://github.com/SmileyChris/easy-thumbnails/releases)
- [Changelog](https://github.com/SmileyChris/easy-thumbnails/blob/master/CHANGES.rst)
- [Commits](SmileyChris/easy-thumbnails@2.8.5...2.9.0)

---
updated-dependencies:
- dependency-name: easy-thumbnails
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements.txt

@@ -187,7 +187,7 @@ drf-yasg==1.21.5
     # via
     #   django-large-image
     #   geotrek (setup.py)
-easy-thumbnails==2.8.5
+easy-thumbnails==2.9
     # via
     #   geotrek (setup.py)
     #   mapentity