corrupt WBM tiles through concurrent writing in parallel processes

[johntruckenbrodt]

In parallel processes WBM tiles might be attempted to be created multiple times causing corrupt files. It needs to be made sure that a WBM tile is only created once and other processes needing it wait until it is finished. Or each process creates its own file and only the first to finish renames it to the final file name.

[johntruckenbrodt]

This has been fixed by requiring pyroSAR 0.25.0 in #192. This new version implements file locking for the underlying functions pyroSAR.auxdata.dem_autoload and pyroSAR.auxdata.dem_create.