fix: set correct main entrypoint (#15)

Author: 43081j

package.json

@@ -3,7 +3,7 @@
   "version": "0.0.0-dev",
   "type": "module",
   "description": "A minimal library for executing processes in Node",
-  "main": "./dist/commonjs/main.js",
+  "main": "./dist/main.js",
   "files": [
     "dist",
     "!dist/node_modules",