Fix line-endings in package.json

[matthewhughes934]

Because I just spent far too much time trying to figure out why npm install added carriage returns to package-lock.json and then git would complain:

warning: in the working copy of 'package-lock.json', CRLF will be
replaced by LF the next time Git touches it

This is simply the result of running:

git add --renormalize package.json

Since the attributes on that file set line endings to simply \n:

$ git check-attr -a package.json
package.json: text: auto
package.json: eol: lf