Deps: update workerpool (#4566)

fixes failing CI tests with Node v5.8

Author: juergba

package-lock.json

@@ -73,7 +73,7 @@
     "supports-color": "8.1.1",
     "which": "2.0.2",
     "wide-align": "1.1.3",
-    "workerpool": "6.0.4",
+    "workerpool": "6.1.0",
     "yargs": "16.2.0",
     "yargs-parser": "20.2.4",
     "yargs-unparser": "2.0.0"