Update GH Actions and fix NodeJS16 deprecation warnings

[offa]

Updates all GH Actions to their latest release which fixes deprecation warnings:

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/checkout@v3. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

💥 Breaking change

CodeCov introduced the requirement for an upload token (breaking changes). Please see documentation or usage guide for how to configure it.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 34.25%. Comparing base (978fa3f) to head (f9d4b22).

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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1349   +/-   ##
=======================================
  Coverage   34.25%   34.25%           
=======================================
  Files          46       46           
  Lines        8408     8408           
  Branches     1178     1178           
=======================================
  Hits         2880     2880           
  Misses       5413     5413           
  Partials      115      115           

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