Bump mkdirp from 1.0.4 to 3.0.1 in /sourcefiles (#1647)

Bumps [mkdirp](https://github.com/isaacs/node-mkdirp) from 1.0.4 to 3.0.1.
- [Changelog](https://github.com/isaacs/node-mkdirp/blob/main/CHANGELOG.md)
- [Commits](isaacs/node-mkdirp@v1.0.4...v3.0.1)

---
updated-dependencies:
- dependency-name: mkdirp
  dependency-version: 3.0.1
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

sourcefiles/package-lock.json

@@ -8,7 +8,7 @@
     "clean-css-cli": "^5.3.0",
     "commander": "^7.2.0",
     "glob-uglifyjs": "^2.0.0",
-    "mkdirp": "^1.0.4",
+    "mkdirp": "^3.0.1",
     "node-sass": "^9.0.0",
     "prettier": "^2.3.1",
     "sass": "^1.53.0"