fixes: #538
'dependency on "ws" version < 2.00 has security flaw in random
number generator'

Note: the engine.io.js file is the generated output of make engine.io.js, and should not be manually modified.

The kind of change this PR does introduce

• a bug fix
• a new feature
• an update to the documentation
• a code change that improves performance
• other

Current behaviour

New behaviour

Other information (e.g. related issues)

From the doc, I ran the following tests, with the resultant output. I don't have a saucelabs account, so it sounds like not all the tests could have been run.

$ npm test

> [email protected] test /Users/pmuellr/Projects/forks/engine.io-client
> gulp test

[20:42:31] Using gulpfile ~/Projects/forks/engine.io-client/gulpfile.js
[20:42:31] Starting 'lint'...
[20:42:33] Finished 'lint' after 1.69 s
[20:42:33] Starting 'test'...


  ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․

  53 passing (4s)

$ ./node_modules/.bin/zuul --local 8080 -- test/index.js

$ make test
[20:47:22] Using gulpfile ~/Projects/forks/engine.io-client/gulpfile.js
[20:47:22] Starting 'lint'...
[20:47:23] Finished 'lint' after 1.49 s
[20:47:23] Starting 'test'...


  ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․

  53 passing (4s)