Improve and simplify CI configuration and fix 3.11 random failures

[mkniewallner]

PR Checklist

• A description of the changes is added to the description of this PR.
• If there is a related issue, make sure it is linked to this PR.
• If you've fixed a bug or added code that should be tested, add tests!
• Documentation in docs is updated

Description of changes

This quite big PR updates the CI configuration in order to simplify it, reduce the workflow duration and more efficiently use the cache. The main changes are:

• fix 3.11 flaky tests in f1140a4 by upgrading pip (example / fixed by Bad metadata: TypeError: expected string or bytes-like object, got 'NoneType' pypa/pip#11352)
• remove unneeded Poetry environment install in e7eed26 and properly set up cache for tox (right now we install dependencies twice, with the second one always being uncached)
• simplify local environment by running all commands through Poetry rather than requiring to get into a shell via poetry shell or a source command in 478359b
• remove unneeded options in install-poetry, as they are already the default
• remove duplicated steps in on-release-main workflow in 2d2ea52 (they are technically already run each time we push to main, so IMO it's not really needed to run them each time we tag a new release)
• move docs dependencies into the main pyproject.toml in acca4cf, making the setup easier locally as users will only have one install to do for all dependencies
• remove duplicated steps in quality job in f27a179, as mypy and pytest are already run in tox
• cache pre-commit dependencies in c230698, to avoid re-installing them on each job run if .pre-commit-config.yaml didn't change

In terms of duration:

• before the changes: https://github.com/fpgmaas/deptry/actions/runs/3456937682
• after the changes: https://github.com/fpgmaas/deptry/actions/runs/3456937682

[codecov-commenter]

Codecov Report

Merging #192 (c230698) into main (e34e72e) will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main    #192   +/-   ##
=====================================
  Coverage   95.5%   95.5%           
=====================================
  Files         29      29           
  Lines        920     920           
  Branches     139     207   +68     
=====================================
  Hits         879     879           
  Misses        27      27           
  Partials      14      14           

Impacted Files	Coverage Δ
deptry/utils.py	90.9% <0.0%> (ø)

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[fpgmaas]

Wow, great work! This is a major improvement to the CI/CD Pipeline. Also nice that we finally get rid of the separate environment for the documentation.. That was a bit of an ugly work-around for some dependency conflicts that I could not be bothered to resolve in the early stages of development.