math/saga: Update to 9.1.1

• Support (new) esri standard world file extension (jpwx, pgwx, ...), reading srs from *.aux.xml
• Fixes for the PySAGA Python package, OpenCV, and more

Changelog: https://sourceforge.net/p/saga-gis/wiki/Changelog%209.1.1/attachment/changelog_saga_9.1.1.txt

Reported by: Repology