fix(plugin-webpack): better webpack-dev-server types

[erickzhao]

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

Knocks off a TODO item.

[codecov]

Codecov Report

Merging #2952 (b9e6b43) into main (d5cf1f2) will increase coverage by 1.28%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##             main    #2952      +/-   ##
==========================================
+ Coverage   70.04%   71.33%   +1.28%     
==========================================
  Files          79       79              
  Lines        2414     2414              
  Branches      452      452              
==========================================
+ Hits         1691     1722      +31     
+ Misses        507      469      -38     
- Partials      216      223       +7     

Impacted Files	Coverage Δ
packages/plugin/webpack/src/WebpackPlugin.ts	38.00% <66.66%> (ø)
packages/maker/base/src/Maker.ts	69.69% <0.00%> (+3.03%)	⬆️
packages/api/core/src/api/lint.ts	65.21% <0.00%> (+4.34%)	⬆️
packages/maker/appx/src/MakerAppX.ts	60.34% <0.00%> (+17.24%)	⬆️
packages/maker/wix/src/MakerWix.ts	81.81% <0.00%> (+40.90%)	⬆️
packages/maker/squirrel/src/MakerSquirrel.ts	76.19% <0.00%> (+47.61%)	⬆️

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