Noissue - Add lint rule arrow-parens to enforce our style

This is style we have been enforcing in review.

Apparently it doesn't make the unamity to add to the eyeo-config style. So I add it here. eyeo/auxiliary/eyeo-coding-style!5 (comment 251765177)

For the summary of what it does:

PASS:

let f = foo =>
{
   return foo;
};

FAIL:

let f = (foo) =>
{
   return foo;
};