v0.21.4

Changelog since 0.21.3:

Fixed

• Allow symbols for use in pagination/prototype front matter #386 (jaredcwhite)
• Ensure the data collection is read first #373 (jaredcwhite)
• Strip out newlines in generated package.json and index.js #369 (eclectic-coding)

Changed

• Resolve postcss-focus-within to v4 #366 (ayushn21)
• Performance refactor of the Webpack helper #382 (jaredcwhite)
• Several documentation improvments thanks to JuanVqz and debashis-biswal