Bump which from 1.3.1 to 4.0.0 (#180)

Bumps [which](https://github.com/npm/node-which) from 1.3.1 to 4.0.0.
- [Release notes](https://github.com/npm/node-which/releases)
- [Changelog](https://github.com/npm/node-which/blob/main/CHANGELOG.md)
- [Commits](npm/node-which@v1.3.1...v4.0.0)

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

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

package.json

@@ -47,7 +47,7 @@
     "rimraf": "2.6.x",
     "vows": "0.7.0",
     "vows-batch-retry": "0.0.4",
-    "which": "^1.3.1"
+    "which": "^4.0.0"
   },
   "scripts": {
     "test": "./test-runner.sh"