Change root package.json#name (#10021)

* Change root package.json#name

I'm pretty sure GitHub's new Dependants feature is based on this package.json. I'm updating it here so it will reflect the new name for the core package.

* Update package.json

package.json

@@ -1,5 +1,5 @@
 {
-  "name": "babel",
+  "name": "babel-core",
   "private": true,
   "license": "MIT",
   "scripts": {