build(pyproject): bump min version of django-mptt to 0.16.0

Signed-off-by: David Wallace <david.wallace@tu-darmstadt.de>

Author: MyPyDavid

pyproject.toml

@@ -48,7 +48,7 @@ dependencies = [
   "django-filter>=23.2,<25.0",
   "django-libsass>=0.9,<1.0",
   "django-mathfilters>=1.0,<2.0",
-  "django-mptt==0.14.0",  # pinned, 0.15 requires Python >= 3.9
+  "django-mptt>=0.16.0,<1.0.0",
   "django-rest-swagger>=2.2,<3.0",
   "django-settings-export>=1.2,<2.0",
   "django-split-settings>=1.2,<2.0",