lxml dependency

[joaoneves10]

When installing pysros on Win10, theres a lxml dependency which sometimes gives an error when trying to install.

The way around it for me was to download lxml version 4.9.0 for python 3.11 here and change the requirements.txt and setup.py files to support lxml version 4.9.0.

[joaoneves10]

For example, the following groups of version clauses are equivalent:
~= 1.4.5, >= 1.4.5, == 1.4.*
So setup.py and requirements.txt expect a lxml version 4.6.* at the moment, so 4.9 won't work.
It should be changed to ~=4.6 so it could expect 4.* such as 4.9 version.

[jgcumming]

This should be resolved from 23.3.1 with the introduction of lxml 4.9.2