Cacheing fails for Github Actions due to API change

[RobFirth]

See: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

So for permacache-poetry:

Run actions/cache@v2.1.6
  with:
    path: ~/.poetry
    key: poetry
  env:
    pythonLocation: /opt/hostedtoolcache/Python/3.9.16/x64
    LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.9.16/x64/lib
Warning: The `save-state` command is deprecated and will be disabled soon. Please upgrade to using Environment Files. For more information see: https://github.blog/changelog/[2](https://github.com/stfc/pre-commit-hooks/actions/runs/4084987471/jobs/7042481773#step:4:2)022-10-11-github-actions-deprecating-save-state-and-set-output-commands/
Cache not found for input keys: poetry

see job here - https://github.com/stfc/pre-commit-hooks/actions/runs/4084987471/jobs/7042481773