Release v2.4.1

[delphaber]

Summary

• Bump version to 2.4.1
• Update CHANGELOG with new entries:
  • FIX: HTML with inline SVG being incorrectly detected as SVG
  • IMPROVED: Replace external test dependencies with local servers

Test plan

• bundle exec rake passes
• gem build fastimage.gemspec succeeds
• Verify CHANGELOG formatting

🤖 Generated with Claude Code

[delphaber]

I'm not 100% sure about the version number though.

Supports for some ruby versions (in the CI) have been dropped, but they were very old versions. If we don't have to consider this dropping, than only a bugfix has been introduced. Then version 2.4.1 would be ok.

If s.required_ruby_version = '>= 1.9.2' is going to be updated to comply with the CI versions, then a major version change is probably necessary.

What do you think?

[sdsykes]

Actually I was already in progress making the release locally, so I've continued that, although I do appreciate you taking the trouble to send this PR.
I didn't update the required ruby version at this time, although as we are no longer testing those old ruby versions it shoudl be done eventually.

[delphaber]

thanks for the release!