Scattertext 0.1.8 requires spacy

[synapticarbors]

With the addition of https://github.com/JasonKessler/scattertext/blob/master/scattertext/__init__.py#L148 into the __init__.py, spacy is now an explicit requirement, because of:

https://github.com/JasonKessler/scattertext/blob/master/scattertext/features/featoffsets/flexible_ngram_features.py#L4

The install requirements of the package should be updated to reflect this.

[JasonKessler]

Thanks for bringing this up and helping support Scattertext. I modified the installation requirements in setup.py to explicitly require spaCy>=3.2.