rasterpic 0.3.1

• New logo.
• Minimum R version required is now 4.1.0.
• Minor internal and documentation improvements.

What's Changed

• Bump actions/checkout from 4 to 5 by @dependabot[bot] in #30
• Bump github/codeql-action from 3 to 4 by @dependabot[bot] in #31
• Bump actions/upload-artifact from 4 to 5 by @dependabot[bot] in #32

Full Changelog: v0.3.0...v0.3.1