Improve build process

[kytta]

Somewhat breaking changes

• Disable sourcemaps on the output
  • I don't know whether anyone depends on it, though
• Minify with esbuild instead of terser
  • This also disables the minification of ESM, which is a good thing, because otherwise the file can't be tree-shaken properly

Other changes

• Make project type module
  • AFAIA, this doesn't really change anything other than the runner used for the config files, etc.
• Remove banner
  • It took unnecessary bytes, and embedding it with esbuild/vite is somewhat buggy
• Update to Vite v4
• Build CSS using Vite
  • this makes the build script leaner
• Remove Browserslist config to always target the defaults
  • the previous config (using last 3 versions instead of last 2 versions) didn't change coverage that much
• Fix code style
• Move PostCSS config to package.json
• Move ESLint config to package.json

Left to do

• release the rc version as @next
• test every use case
  • browser import via ESM
  • browser import via IIFE
  • browser import via UMD
  • Node import via ESM
  • Node import via UMD

[kytta]

v2.0.2-0 is out, let's test...

[github-actions]

size-limit report 📦

Path	Size
./dist/shareon.min.css	5.43 KB (added)
./dist/shareon.es.js	837 B (added)