chore(deps-dev): bump vitest and @vitest/coverage-istanbul

Bumps [vitest](https://github.com/vitest-dev/vitest/tree/HEAD/packages/vitest) and [@vitest/coverage-istanbul](https://github.com/vitest-dev/vitest/tree/HEAD/packages/coverage-istanbul). These dependencies needed to be updated together.

Updates `vitest` from 1.6.0 to 2.1.8
- [Release notes](https://github.com/vitest-dev/vitest/releases)
- [Commits](https://github.com/vitest-dev/vitest/commits/v2.1.8/packages/vitest)

Updates `@vitest/coverage-istanbul` from 1.6.0 to 2.1.8
- [Release notes](https://github.com/vitest-dev/vitest/releases)
- [Commits](https://github.com/vitest-dev/vitest/commits/v2.1.8/packages/coverage-istanbul)

---
updated-dependencies:
- dependency-name: vitest
  dependency-type: direct:development
  update-type: version-update:semver-major
- dependency-name: "@vitest/coverage-istanbul"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

package.json

@@ -61,7 +61,7 @@
     "@size-limit/preset-small-lib": "^11.0.2",
     "@size-limit/time": "^11.0.2",
     "@types/node": "^22.0.0",
-    "@vitest/coverage-istanbul": "^1.6.0",
+    "@vitest/coverage-istanbul": "^2.1.8",
     "@vitest/ui": "^1.6.0",
     "all-contributors-cli": "^6.26.1",
     "lefthook": "^1.6.1",
@@ -73,7 +73,7 @@
     "ts-node": "^10.9.1",
     "tslib": "^2.6.2",
     "typescript": "^5.2.2",
-    "vitest": "1.6.0"
+    "vitest": "2.1.8"
   },
   "size-limit": [
     {