v4.0.0

Highlights

• New: Added sponsor button (pass type=sponsor)
• New: Updated the font stack to a more modern one
• Breaking: Dropped ancient CSS vendor prefixes and IE < 10 support; the button will still work on IE9, but it won't look perfect, IE < 9 no longer works.
• Enhancement: Reduced filesize approximately -20% off the uncompressed github-btn.html's size (6849 -> 5419 bytes)
• Enhancement: When count=true is not passed, we now don't make any GitHub API request which should significantly improve page load times

Detailed changes

• Improved button's accessibility:
  • counter is hidden with aria-hidden if it's empty
  • a title is added in the iframe
• Improve button's HTML
  • add doctype
  • add lang
  • add charset
  • add rel="noopener noreferrer" for external links
  • remove aria-label since we set it via JS
• Improve button's CSS:
  • the embedded SVG is no longer base64-encoded (-45% off the uncompressed SVG)
  • the embedded SVG is optimized with SVGO (approximately -25% off the compressed SVG, -28% off the uncompressed SVG)
  • the CSS is streamlined
• Improved button's JS:
  • we no longer make unneeded GitHub API calls, for example if you don't pass query=true
  • add a few fail-safe checks
  • switched to Node.textContent since we weren't adding HTML
  • wrap the code in an IIFE so that the minifier mangles the variables properly
  • switch to strict mode
• Build:
  • it should be generally easier to work on the project locally; npm i && bundle i to get started
  • replace gulp with npm scripts
  • add CSS/Sass linting with Stylelint
  • and JS linting with xo
  • add a watch script
  • update Jekyll to v4.0.0
  • add CI for tests and docs deployments
• Docs:
  • the docs are HTML5 valid
  • the docs are WCAG2AA valid
  • add link rel=canonical
  • add meta generator tag
  • switch to Sass
  • inline the docs CSS