chore: simplify babel script

Author: aminya

package.json

@@ -12,7 +12,7 @@
     "test.lint": "eslint .",
     "test": "npm run babel && atom --test spec",
     "clean": "shx rm -rf dist",
-    "babel": "npm run clean && shx cp -r src dist && cross-env NODE_ENV=development cross-env BABEL_KEEP_MODULES=false babel dist --out-dir dist",
+    "babel": "cross-env BABEL_KEEP_MODULES=false babel ./src --out-dir ./dist",
     "dev": "npm run clean && cross-env NODE_ENV=development cross-env BABEL_KEEP_MODULES=true rollup -c -w",
     "build": "npm run clean && cross-env NODE_ENV=production cross-env BABEL_KEEP_MODULES=true rollup -c ",
     "build-commit": "build-commit -o dist",