MaartenGr/BERTopic: v0.9.4

A number of fixes, documentation updates, and small features:

• Expose diversity parameter
  • Use BERTopic(diversity=0.1) to change how diverse the words in a topic representation are (ranges from 0 to 1)
• Improve stability of topic reduction by only computing the cosine similarity within c-TF-IDF and not the topic embeddings
• Added property to c-TF-IDF that all IDF values should be positive (#351)
• Major documentation overhaul (mkdocs, tutorials, FAQ, images, etc. ) (#330)
• Additional logging for .transform (#356)

• Drop python 3.6 (#333)
• Relax plotly dependency (#88)
• Improve stability of .visualize_barchart() and .visualize_hierarchy()