chore(release): Bumped to Version 15.9.0

# [15.9.0](v15.8.0...v15.9.0) (2024-10-29)

### Features

* **Business Trip Region:** add fields "Valid From" and "Disabled" ([e6732f7](e6732f7))
* **Business Trip Region:** show rates in list view ([0a89a5d](0a89a5d))
* import Business Trip Regions after install and via patch ([27a35da](27a35da))

erpnext_germany/__init__.py

@@ -1 +1 @@
-__version__ = "15.8.0"
+__version__ = "15.9.0"