Poor memory management with dask 2021.04.0

[hakonanes]

All EBSD pattern processing methods, like remove_static_background(), didn't increase memory by much with dask 2021.03.0 and earlier, while with 2021.04.0, the memory usage increases drastically.

I believe it is related to dask/dask#7583. Apparently, from the wording in the second comment in that issue, the current implementation of dask array chunking before calls to map_blocks() and finally store() is made by a "newbie", meaning me...

@magnunor, do you experience any memory issues with pyxem using dask 2021.04.0?

[hakonanes]

I leave this issue open until we remove the restriction on the newest dask version in setup.py, i.e. when the above referenced issue is fixed.

[hakonanes]

Patch release v0.3.4 is now released, where dask is pinned to <=2021.03.1

[hakonanes]

Have to check, but this should be fixed in dask/dask#8040! That fix will be included in version 2021.8.1, I think, so we should be fine by updating the dependencies to allow from that and above.

[hakonanes]

Fixed in #418.