fix: webpack 5 deprecated warnings

[sorrycc]

Checklist

• npm test passes
• tests are included
• documentation is changed or added
• commit message follows commit guidelines

Description of change

• any feature?
• close https://github.com/umijs/umi/ISSUE_URL

[codecov]

Codecov Report

Merging #6227 (a6bc6f1) into master (92c6f88) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6227   +/-   ##
=======================================
  Coverage   84.40%   84.40%           
=======================================
  Files         153      153           
  Lines        3470     3470           
  Branches      942      942           
=======================================
  Hits         2929     2929           
  Misses        531      531           
  Partials       10       10           

---

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 92c6f88...a6bc6f1. Read the comment docs.