fix(deps): update socket.io to version 2.0.3.

[johnjbarton]

This is a duplicate of @kevinsalter PR #2821. I am re-sending after appveyor fixup.
(We don't seem to have the ability to retry appveyor builds).

Fixes #2777

[dignifiedquire]

@zzo @johnjbarton did you check that all IE versions are still supported with this new socket.io version?

Users currently rely on support back to IE7, where as socket.io doesn't test those currently: https://github.com/socketio/socket.io#cross-browser

Looks like the reason for this is socketio/engine.io-client#581 saucelabs doesn't support testing on IE 7 anymore.

@mgol could you check if things are still working fine for you on the latest master please?

[pedrosimoes-nbr]

@dignifiedquire et al. thanks for your good work. Are you planning to quickly release this fix on the npm repository? At least for me, it solved the related issue.

[herringtown]

any status updated on this?

[dignifiedquire]

@herringtown 2.0 was released, which includes this fix

[pedrosimoes79]

Thks

[mgol]

@dignifiedquire Sorry for the late reply. I've tried Karma 2.0 but IE 7 still didn't run correctly. See the Travis run and the relevant commit.