fix: Update supported python versions in front page badge

[Dev-iL]

Changes

• Remove python 3.8, 3.9 and add 3.13, 3.14 instead
• Add spaces on both sides of the version numbers
• Update python version constraint for vaex to reflect the project's supported python versions

How I tested this

Notes

Checklist

• PR has an informative and human-readable title (this will be pulled into the release notes)
• Changes are limited to a single goal (no scope creep)
• Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future TODOs are captured in comments
• Project documentation has been updated if adding/changing functionality.