Update dependency which to v4 (#443)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package-lock.json

@@ -551,7 +551,7 @@
     "antlr4ts": "^0.5.0-alpha.4",
     "semver": "^7.3.8",
     "vscode-languageclient": "^8.0.2",
-    "which": "^3.0.0"
+    "which": "^4.0.0"
   },
   "devDependencies": {
     "@types/antlr4": "4.11.2",