Update sockjs dependency to fix auditjs security vulnerability warning

[fwielstra]

What kind of change does this PR introduce?

Updates sockjs to 0.3.19

Did you add or update the examples/?

nay

Summary

#1177

Does this PR introduce a breaking change?
It shouldn't

Other information

[jsf-clabot]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #1178 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1178   +/-   ##
=======================================
  Coverage   76.31%   76.31%           
=======================================
  Files           5        5           
  Lines         477      477           
  Branches      154      154           
=======================================
  Hits          364      364           
  Misses        113      113

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7e89442...3f923ad. Read the comment docs.

[shellscape]

@fwielstra thanks for the PR. we'll still have to go through the /examples using this sha to make sure that it doesn't break anything, even though it shouldn't. sockjs in this project is a rather fragile pain point, so we have to be extra certain. please understand that may take a while, as our efforts are focused on v3 (which removes SockJS as a dependency) at the moment. it's also worth noting that this vulnerability shouldn't be an issue for webpack-dev-server, as it should never be run in anything but a dev/test environment, and certainly not exposed to the public.

[fwielstra]

That's okay, if socksjs is removed completely that will also resolve the issue. We also only use this project in development, and are ignoring the security warning - we'd prefer to just ignore it, but I've not been able to find the vunlerability ID to put in the auditjs whitelist (see this issue).

So yeah, no worries, take your time or just close this issue when 3.0 is out, I'm sure we'll be able to upgrade soon after. Thanks!