fix: explicitly depend on @babel/parser

Since we import it directly we must depend on it directly, since without this the install may not work with some `node_modules` layouts (i.e. pnpm).

package.json

@@ -67,6 +67,7 @@
   "dependencies": {
     "@babel/core": "^7.1.6",
     "@babel/generator": "^7.1.6",
+    "@babel/parser": "^7.1.6",
     "@babel/preset-env": "^7.1.6",
     "@babel/preset-typescript": "^7.1.0",
     "@babel/traverse": "^7.1.6",
@@ -99,4 +100,4 @@
       "pre-commit": "lint-staged"
     }
   }
-}
+}