Fix HtmlWebpackPlugin error

[Hypnosphi]

Issue: #3148 (comment)

@peet86 is there any reproduction code that we could add to our examples to check that the fix works?

[codecov]

Codecov Report

Merging #3328 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3328   +/-   ##
=======================================
  Coverage   35.63%   35.63%           
=======================================
  Files         472      472           
  Lines       10122    10122           
  Branches      956      945   -11     
=======================================
  Hits         3607     3607           
- Misses       5899     5925   +26     
+ Partials      616      590   -26

Impacted Files	Coverage Δ
app/vue/src/server/config/webpack.config.js	0% <ø> (ø)	⬆️
app/polymer/src/server/config/webpack.config.js	0% <ø> (ø)	⬆️
app/mithril/src/server/config/webpack.config.js	0% <ø> (ø)	⬆️
...p/polymer/src/server/config/webpack.config.prod.js	0% <ø> (ø)	⬆️
app/vue/src/server/config/webpack.config.prod.js	0% <ø> (ø)	⬆️
app/react/src/server/config/webpack.config.prod.js	0% <ø> (ø)	⬆️
...p/mithril/src/server/config/webpack.config.prod.js	0% <ø> (ø)	⬆️
app/angular/src/server/config/webpack.config.js	0% <ø> (ø)	⬆️
...p/angular/src/server/config/webpack.config.prod.js	0% <ø> (ø)	⬆️
app/react/src/server/config/webpack.config.js	0% <ø> (ø)	⬆️
... and 72 more

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