Simplify postcompile script to use echo instead of node -e

Author: glasser

package.json

@@ -31,7 +31,7 @@
   },
   "scripts": {
     "compile": "tsc --build tsconfig.build.json",
-    "postcompile": "node -e \"const fs = require('fs'); fs.writeFileSync('dist/esm/package.json', JSON.stringify({type:'module'})); fs.writeFileSync('dist/cjs/package.json', JSON.stringify({type:'commonjs'}));\"",
+    "postcompile": "echo '{\"type\":\"module\"}' > dist/esm/package.json && echo '{\"type\":\"commonjs\"}' > dist/cjs/package.json",
     "clean": "git clean -dfqX",
     "prepack": "npm run compile",
     "prettier-check": "prettier --check .",