Update CHANGELOG

Author: RyanZim

CHANGELOG.md

@@ -1,3 +1,21 @@
+3.0.0-beta / 2017-03-17
+==========
+
+## Breaking Changes
+- Uses https://github.com/michael-ciniawsky/postcss-load-config for config files. Dropped support for the v2 config file format.
+- `--use` accepts a list of plugins. This may cause issues if you have your list of css files at the end of your command.
+- Can't pass options to plugins via `--plugin.key=value` anymore, use a config file.
+- Changed usage of the `--map` option; use `--map` for external sourcemaps, `--no-map` to disable all maps. Inline sourcemaps are default.
+- Writes to stdout if neither `-o`, `--dir`, or `--replace` is set.
+- Removed the `--local-plugins` flag; same result can be achieved with `postcss.config.js`.
+- Removed the global `watchCSS` handler, plugins that import/rely on other files should use a `dependency` message instead.
+
+## New Features
+- `--ext` (`-x`) option allows you to set the file extensions for your output files when using `--dir`.
+- `--env` allows you to set `NODE_ENV` in a cross-platform manner.
+
+Migration guide: https://github.com/postcss/postcss-cli/wiki/Migrating-from-v2----v3
+
 2.6.0 / 2016-08-30
 ==================