Revert "Change indentation of `package.json` to 4 spaces."
Revert "Change indentation of `package.json` to 4 spaces."

This reverts commit fc9f34d7f0c6cfce203044ac5aaa77b1e33b125b. It seems
that `grunt-release` also modifies the indentation of `package.json`.

joshuaspence/lesscsslint