Use ubuntu-22:04 and checkout@v4 in omero_plugin.yml

[will-moore]

Taking some changes from https://github.com/ome/omero-figure/pull/537/files to try and fix build failures at https://github.com/IDR/idr-gallery/actions/runs/8985335098/job/24679106361

Collecting wheel
  Downloading wheel-0.43.0-py3-none-any.whl.metadata (2.2 kB)
Downloading wheel-0.43.0-py3-none-any.whl (65 kB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 65.8/65.8 kB 3.[9](https://github.com/IDR/idr-gallery/actions/runs/8985335098/job/24679106361#step:5:10) MB/s eta 0:00:00
Installing collected packages: wheel
Successfully installed wheel-0.43.0
Traceback (most recent call last):
  File "/home/runner/work/idr-gallery/idr-gallery/setup.py", line 24, in <module>
    from setuptools import setup, find_packages
ModuleNotFoundError: No module named 'setuptools'
Error: Process completed with exit code 1.

[jburel]

Replaced by #48