build(deps-dev): Bump @flex-development/mkbuild

Bumps [@flex-development/mkbuild](https://github.com/flex-development/mkbuild) from 1.0.0-alpha.20 to 1.0.0-alpha.21.
- [Release notes](https://github.com/flex-development/mkbuild/releases)
- [Changelog](https://github.com/flex-development/mkbuild/blob/main/CHANGELOG.md)
- [Commits](flex-development/mkbuild@1.0.0-alpha.20...1.0.0-alpha.21)

---
updated-dependencies:
- dependency-name: "@flex-development/mkbuild"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -91,7 +91,7 @@
     "@flex-development/commitlint-config": "1.0.1",
     "@flex-development/decorator-regex": "2.0.0",
     "@flex-development/esm-types": "2.0.0",
-    "@flex-development/mkbuild": "1.0.0-alpha.20",
+    "@flex-development/mkbuild": "1.0.0-alpha.21",
     "@flex-development/mlly": "1.0.0-alpha.17",
     "@flex-development/pathe": "2.0.0",
     "@flex-development/toggle-pkg-type": "2.0.1",