Upgrade werkzeug for security reasons

[MRichards99]

Description

This morning I noticed that the safety job on this repo's CI is failing due to an old version of werkzeug (see https://github.com/ral-facilities/datagateway-api/runs/4066918019?check_suite_focus=true). I have upgraded the version of this to satisfy that job.

Testing Instructions

• Review code
• Check GitHub Actions build
• If icatdb Generator Script Consistency Test CI job fails, is this because of a
  deliberate change made to the script to change generated data (which isn't
  actually a problem) or is there an underlying issue with the changes made?
• Review changes to test coverage

Agile Board Tracking

Connect to #{issue number}

[MRichards99]

Ignore the failing check from 'Semantic Pull Request'. This tool will be used for the versioning i.e. once #242 is closed.

[codecov]

Codecov Report

Merging #278 (ca14c35) into bugfix/default-python-version (42c29be) will not change coverage.
The diff coverage is n/a.

@@                      Coverage Diff                       @@
##           bugfix/default-python-version     #278   +/-   ##
==============================================================
  Coverage                          91.23%   91.23%           
==============================================================
  Files                                 32       32           
  Lines                               2395     2395           
  Branches                             205      205           
==============================================================
  Hits                                2185     2185           
  Misses                               186      186           
  Partials                              24       24           

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