Proposal: Consider removing casts to Error when catching

[PatrickShaw]

Was investigating this library and found that orWhen accepts an Error. I took a look at the internals of this library and found that there's a cast to Error in

cockatiel/src/common/Executor.ts

Line 67 in 03614ab

const handled = this.errorFilter(error as Error);

From what I can see there's technically no guarantee that what's being throw is an Error. Someone could, for instance, if they really wanted do, say throw 'some error message' - Not ideal but sometimes we have no control over what's being thrown as the thrown error might live in, say, a third party library.

As such, I propose that we replace the use of Error + the cast to unknown