Fix TCP appender with Webpack and Typescript

[techmunk]

This is much like the fix for #1008 and #816
I've also included typescript typings for the TCP appender. I can remove these if you prefer.

There are some other core appenders that are also not in this list, however I'm unsure if this was intentional or by accident so have only included the one I'm currently concerned with and tested for now.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@f8d46a9). Click here to learn what that means.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master    #1028   +/-   ##
=========================================
  Coverage          ?   98.36%           
=========================================
  Files             ?       25           
  Lines             ?     1041           
  Branches          ?        0           
=========================================
  Hits              ?     1024           
  Misses            ?       17           
  Partials          ?        0           

Impacted Files	Coverage Δ
lib/appenders/index.js	98.55% <100.00%> (ø)
lib/logger.js	97.82% <0.00%> (ø)
lib/appenders/adapters.js	94.44% <0.00%> (ø)
lib/appenders/fileSync.js	94.73% <0.00%> (ø)
lib/appenders/dateFile.js	100.00% <0.00%> (ø)
lib/appenders/tcp.js	91.30% <0.00%> (ø)
lib/appenders/stdout.js	100.00% <0.00%> (ø)
lib/appenders/logLevelFilter.js	100.00% <0.00%> (ø)
lib/levels.js	100.00% <0.00%> (ø)
lib/layouts.js	99.05% <0.00%> (ø)
... and 16 more

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[guntram]

Why was this not merged?

[swappler-sudo]

What's the status?

[lamweili]

@swappler-sudo Fixed in log4js@6.4.0