chore: use slim renovate with constraints

[huxuan]

1. Use slim version of renovate container image
2. Constraints python and pdm version in Renovate.
3. Manage the pdm version in the renovate constraints by renovate.
4. Unify pdm version specified in pdm-project/setup-pdm GitHub Actions.
5. Update related documentation.

• GitHub Actions: https://github.com/huxuan/ss-python/actions/runs/9203981154/job/25316623373
  • Search keyword "install-tool" and "constraints" to see how it takes effect
• Pull request:
  • build(deps): update dependency pdm to v2.15.3 huxuan/ss-python#108
  • build(deps): lock file maintenance huxuan/ss-python#111

With slim renovate docker image, it should saves time for container initialization. With fixed version of Python and pdm, it should bring more reproducibility.

[msclock]

It seems it cut a half of time comsuming. Great work.👍 I'd like to adopt it for ss-cpp later.