pmlmodelling/nctoolkit: v0.8.6

This is a minor releases that tidies up some issues and has some method enhancements. The regrid and to_latlon methods can now be more efficient for multi-file datasets where all files have the same grid. Previously, the methods identified the grids for all methods, which is obviously inefficient if they are all the same. You can now set the one_grid argument to True, which will result in the methods assuming all files have the same grid, and only the first file being checked. There was an issue with multi-file datasets in parallel in Python 3.8 and 3.9. A confusing TypeError was being thrown due to signalling issues by multiprocessing. This gave the impression there was a problem with processing when there wasn't one. This problem is now fixed