Remove usage of deprecated utils to fix warnings in Node 22

[KidkArolis]

Fixes the following warnings when run in Node@22

(Use `node --trace-deprecation ...` to show where the warning was created)
(node:20281) [DEP0053] DeprecationWarning: The `util.isObject` API is deprecated. Please use `arg !== null && typeof arg === "object"` instead.
(node:20281) [DEP0044] DeprecationWarning: The `util.isArray` API is deprecated. Please use `Array.isArray()` instead.
(node:20281) [DEP0055] DeprecationWarning: The `util.isRegExp` API is deprecated. Please use `arg instanceof RegExp` instead.
(node:20281) [DEP0047] DeprecationWarning: The `util.isDate` API is deprecated.  Please use `arg instanceof Date` instead.

[mdouglass]

Just saw this which addresses my issue in #765. Thanks!