Added support for Python versions 3.8 - 3.11

[adamnellis]

[sc-132159]

Added Python 3.8, 3.9, 3.10, 3.11

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The nltk and sumy libraries needed bumping for the newer versions of Python.

• I only bumped them for newer versions of Python that this plugin did not support before now
• According to their docs we could bump them for older Pythons as well, but I left them to be 100% sure of not changing anything for users who are on older versions of Python
  • latest nltk says it supports Python 3.7
  • latest sumy says it supports Python 3.6

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Tested this by:

• Created my own project https://staging-design.qa.managedinstances.dkucloud-dev.com/projects/PLUGINTESTNLPSUMMARIZATION/
• Tested on Python versions 2.7, 3.6, 3.7, 3.8, 3.9, 3.10, 3.11
• Ran the plugin with methods textrank and lsa
• Compared the outputs by eye
• The klsum method took 45 mins to run, so I only ran it on Python 2.7 and 3.11
• The number of sentences parameter looks trivial, so I only tested it on textrank and lsa, for Python 2.7 and 3.11

[shortcut-integration]

This pull request has been linked to Shortcut Story #132159: [text-summarization][AIML] necessary update.

[AgatheG]

Tested from 2.7 to 3.11, no issues ✅