chore(deps-dev): bump karma-sourcemap-loader (axios#7360)

Bumps the development_dependencies group with 1 update in the / directory: [karma-sourcemap-loader](https://github.com/demerzel3/karma-sourcemap-loader).


Updates `karma-sourcemap-loader` from 0.3.8 to 0.4.0
- [Changelog](https://github.com/demerzel3/karma-sourcemap-loader/blob/master/CHANGELOG.md)
- [Commits](https://github.com/demerzel3/karma-sourcemap-loader/commits/0.4.0)

---
updated-dependencies:
- dependency-name: karma-sourcemap-loader
  dependency-version: 0.4.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: development_dependencies
...

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Author: dependabot[bot]