Replaces the `zombie-pigmen` entry in the `spec1` wave of the default
configuration with `slimes-big`. This is due to the pig zombie rework
into piglins, which makes the custom name a little flaky. If we ever
decide to ditch the custom names somehow, this will probably make such a
transition a little easier.
While `slimes-big` is also a custom name, so are `powered-creepers` and
`angry-wolves`, but at least they are "API stable" in comparison, which
is really what this change is about.
Andreas Troelsen
36237ebe2d