MaartenGr/BERTopic: v0.16.3

<h1><b>Highlights</a></b></h1>

• Simplify zero-shot topic modeling by @ianrandman in #2060
• Option to choose between c-TF-IDF and Topic Embeddings in many functions by @azikoss in #1894
  • Use the use_ctfidf parameter in the following function to choose between c-TF-IDF and topic embeddings:
    • hierarchical_topics, reduce_topics, visualize_hierarchy, visualize_heatmap, visualize_topics
• Linting with Ruff by @afuetterer in #2033
• Switch from setup.py to pyproject.toml by @afuetterer in #1978
• In multi-aspect context, allow Main model to be chained by @ddicato in #2002

<h1><b>Fixes</a></b></h1>

• Added templates for issues and pull requests
• Update River documentation example by @Proteusiq in #2004
• Fix PartOfSpeech reproducibility by @Greenpp in #1996
• Fix PartOfSpeech ignoring first word by @Greenpp in #2024
• Make sklearn embedding backend auto-select more cautious by @freddyheppell in #1984
• Fix typos by @afuetterer in #1974
• Fix hierarchical_topics(...) when the distances between three clusters are the same by @azikoss in #1929
• Fixes to chain strategy example in outlier_reduction.md by @reuning in #2065
• Remove obsolete flake8 config and update line length by @afuetterer in #22066