refactor(npm): start v2

This commit isn't a breaking change, but the ones before it were. This commit is used to tell
semantic-release to increment the major version.

BREAKING CHANGE: removed core rules

package.json

@@ -10,7 +10,7 @@
     "branch": "dev"
   },
   "scripts": {
-    "build": "babel --version && babel lib -d dist --optional runtime",
+    "build": "babel lib -d dist --optional runtime",
     "build:w": "npm run build -- -w",
     "build:istanbul": "npm run build -- --auxiliary-comment-before \"istanbul ignore next\"",
     "check-coverage": "istanbul check-coverage",