Fixes package.json 'main' field.

Author: ctrlplusb

package.json

@@ -4,7 +4,7 @@
  "description":
  "Walk a React element tree, executing a provided function against each node.",
  "license": "MIT",
- "main": "commonjs/index.js",
+ "main": "dist/react-tree-walker.js",
  "files": ["*.js", "*.md", "dist"],
  "repository": {
  "type": "git",