Fix async package at 1.5.2

[patrickhpan]

To avoid breaking change to async.whilst. In 1.5.2 and earlier, the first function of async.whilst returns true while the second function is to be called, but in later version of async the function itself takes a callback as argument and calls it to determine whether to continue to the second function.

[patrickhpan]

node_airtunes/lib/udp_servers.js

Line 109 in 7e2d5f6

function() { return to_bind.length > 0; },

In the current version (as of May 2021) of async, the first function takes a callback as argument (see docs). In 1.5.2, returning a boolean is the expected behavior. The result of using a modern version of async is that the second callback will never be called, preventing the ports from ever being bound.

This should fix the issue in babelpod here: afaden/babelpod#17