rasterpic 0.5.0

• Package documentation was reviewed and updated with AI-assisted editing.
• rasterpic_img() is now an S3 generic with methods for supported input
  classes (#39).
• rasterpic_img() now supports stars objects.

What's Changed

• Bump codecov/codecov-action from 5 to 6 by @dependabot[bot] in #38
• Move rasterpic_img to generic by @dieghernan in #39

Full Changelog: v0.4.0...v0.5.0