Fix Pip Install Issues

[MRichards99]

This PR will close #467

Description

These changes allow DataGateway API to be installed using pip install - the fix is simply just to explicitly state which version of Flask should be used instead of the installation process trying to figure that out. Normally that wouldn't be an issue, but we're having to use quite an old version of Flask that still supports Python 3.6. There's also some updates to poetry.lock as a result - a lot of that is just upgrading other dependencies as the file hasn't changed in a little while.

I've added a job to the CI to keep track of this - you can see in this run (before Flask was pinned), that new job fails on Python 3.8+, giving the same error that was originally found but the CI now passes.

When the PR is merged, it will create v9.0.2 so you'll be able to use this new version with SciGateway Ansible.

Testing Instructions

Take a look at the CI and check you're happy with it and try to pip install the API on your own machine.

• 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 here an underlying issue with the changes made?
• Review changes to test coverage
• Does this change mean a new patch, minor or major version should be made? If so, does one of the commit messages feature fix:, feat: or BREAKING CHANGE: so a release is automatically made via GitHub Actions upon merge?

Agile Board Tracking

Connect to #467

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (4a29dd5) 96.66% compared to head (05b3e13) 96.66%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #468   +/-   ##
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  Coverage   96.66%   96.66%           
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  Files          39       39           
  Lines        3242     3242           
  Branches      317      317           
=======================================
  Hits         3134     3134           
  Misses         80       80           
  Partials       28       28           

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[louise-davies]

LGTM - thanks for fixing this! It will be helpful for future machine migrations