[fix] added import/prefer-default-export (sveltejs#119)

Author: jis3r

OTHER_PLUGINS.md

@@ -16,6 +16,7 @@ These rules are known to not work correctly together with this plugin:
 - `import/no-duplicates`
 - `import/no-mutable-exports`
 - `import/no-unresolved` when using `svelte3/named-blocks`, pending [this issue](https://github.com/benmosher/eslint-plugin-import/issues/1415)
+- `import/prefer-default-export`
 
 If you're using them on other linted files, consider [adding `overrides` for them for Svelte components](https://eslint.org/docs/user-guide/configuring/configuration-files#how-do-overrides-work).