math/saga: Update to 7.6.3

From ChangeLog:
https://sourceforge.net/p/saga-gis/wiki/Changelog%207.6.3/attachment/changelog_saga_7.6.3.txt

• bug fix in statistics_kriging/variogram_dialog
• omp issue with compiling proj<6
• bug fix for export of grid to kml
• check gcc version for wksp_tool_manager
• add russian translation

PR: 246384
Submitted by: rhurlin@gwdg.de (maintainer)