refactor: i18n Webpack Plugin Webpack 4.x compatibility

[joshwiens]

• Fixes for Webpack 4.x
• Drops support for NodeJS 4.x
• Sets minimum peerDep to Webpack 3.x

BREAKING CHANGE: Sets engines to "node": ">= 6.9.0 || >= 8.9.0"
BREAKING CHANGE: Drops support for Webpack v2.x

[codecov]

Codecov Report

Merging #68 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #68   +/-   ##
=======================================
  Coverage   95.06%   95.06%           
=======================================
  Files           4        4           
  Lines          81       81           
  Branches       23       23           
=======================================
  Hits           77       77           
  Misses          4        4

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[MrStarktastic]

Any update on when this is gonna be merged into master?
I'm asking due to a warning I'm getting when using webpack 4:
DeprecationWarning: Tapable.plugin is deprecated. Use new API on .hooks instead
Tracing the deprecation warning shows that it originates from I18nPlugin.apply

[mistadikay]

Guys, do you need any help with this one?

[adriangalera]

waiting for this PR to be merged

[codecov]

Codecov Report

Merging #68 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #68   +/-   ##
=======================================
  Coverage   95.06%   95.06%           
=======================================
  Files           4        4           
  Lines          81       81           
  Branches       23       23           
=======================================
  Hits           77       77           
  Misses          4        4

---

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 5c9c7d5...c41c10a. Read the comment docs.