build(deps-dev): Bump vitest from 2.1.5 to 2.1.6 in the vitest group

Bumps the vitest group with 1 update: [vitest](https://github.com/vitest-dev/vitest/tree/HEAD/packages/vitest).


Updates `vitest` from 2.1.5 to 2.1.6
- [Release notes](https://github.com/vitest-dev/vitest/releases)
- [Commits](https://github.com/vitest-dev/vitest/commits/v2.1.6/packages/vitest)

---
updated-dependencies:
- dependency-name: vitest
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: vitest
...

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

package.json

@@ -208,7 +208,7 @@
     "typescript-eslint": "8.16.0",
     "unified": "11.0.5",
     "vfile": "6.0.3",
-    "vitest": "2.1.5",
+    "vitest": "2.1.6",
     "yaml-eslint-parser": "1.2.3"
   },
   "packageManager": "[email protected]",