Add `integer-simple` to `core_packages`

[aherrmann]

The integer-simple package is part of the GHC distribution. However, it is not listed in the core_packages section of the Stackage LTS 12.4 snapshot as generated by the Stackage.hs script. It can be manually added to the core_packages as follows.

WORKSPACE:

load("@ai_formation_hazel//:hazel.bzl", "hazel_repositories")
load("//hazel:packages.bzl", "core_packages", "packages")
hazel_repositories(
  core_packages = core_packages + {
    "integer-simple": "0.1.1.1",
  },
  packages = packages,
  ...
)

Since integer-simple is part of the GHC distribution, maybe it should already be part of core_packages?

[thumphries]

Is integer-simple always part of the GHC distribution? I was under the impression that it was a conditional inclusion.

In any case, let's try it and see what happens.