Package JSON sync alters array formatting

[HypeMC]

Currently, each time composer install is run, it changes the formatting of arrays keys in package.json:

{
-   "browserslist": [
-      "defaults"
-   ]
+   "browserslist": ["defaults"]
}

This is especially annoying since npm install actually reverts it to the previous formatting, so it's a constant "battle" between the two package managers.

[nicolas-grekas]

Thank you @HypeMC.