Improve distributed dist directory (#234)

* Improve dist

- rename .es.js to .esm.js
- removed jsnext:main
- simplified rollup config

* Tweak files and revert external

packages/rollup-plugin-babel/package.json

@@ -3,13 +3,10 @@
   "version": "4.0.0-beta.7",
   "description": "Seamless integration between Rollup and Babel.",
   "main": "dist/rollup-plugin-babel.cjs.js",
-  "module": "dist/rollup-plugin-babel.es.js",
-  "jsnext:main": "dist/rollup-plugin-babel.es.js",
+  "module": "dist/rollup-plugin-babel.esm.js",
   "files": [
     "src",
-    "dist/rollup-plugin-babel.cjs.js",
-    "dist/rollup-plugin-babel.es.js",
-    "README"
+    "dist"
   ],
   "keywords": [
     "rollup-plugin",

packages/rollup-plugin-babel/rollup.config.js

@@ -1,24 +1,18 @@
 import buble from 'rollup-plugin-buble';
+import pkg from './package.json';
 
-var pkg = require('./package.json');
-var externalDeps = Object.keys(Object.assign({}, pkg.dependencies, pkg.peerDependencies));
-var nodeDeps = ['path'];
-var external = externalDeps.concat(nodeDeps);
+const externalDeps = Object.keys(
+	Object.assign({}, pkg.dependencies, pkg.peerDependencies)
+);
+const nodeDeps = ['path'];
+const external = externalDeps.concat(nodeDeps);
 
 export default {
-	input: 'src/index.js',
+	input: './src/index.js',
 	plugins: [ buble({ objectAssign: 'Object.assign' }) ],
-	external: external,
+	external,
 	output: [
-		{
-			file: 'dist/rollup-plugin-babel.cjs.js',
-			format: 'cjs',
-			sourcemap: true,
-		},
-		{
-			file: 'dist/rollup-plugin-babel.es.js',
-			format: 'es',
-			sourcemap: true,
-		},
+		{ file: pkg.main, format: 'cjs', sourcemap: true },
+		{ file: pkg.module, format: 'esm', sourcemap: true },
 	]
 };