Release v0.9.0

Changes since v0.8.1

API

• Fix a bug where data files get deleted when they're edited via the Raw Editor mode #486 (props to @lexoyo 👍)
• Add support for Jekyll 4.0 #492 (Thanks @zocoi)
• Update Jekyll server monkey-patch to mirror Core #499

User Interface

• Add meta charset="utf-8" to the interface views. #485 (Thanks @RDIL)

Development

• Use rubocop-jekyll to enforce Jekyll's styles #497
• Upgrade Node dependencies to allow using Node 10 #500

Documentation

• Update links in README to https:// protocol #488 (Thanks @coliff)
• Fix URL to docs about installing plugins #495
• Fix plugin name in documentation #496 (Thanks @ismailarilik)