CI tests on deprecated GHC versions

Looks like CI needs some update... https://github.com/haskell/directory/blob/6442a3cf04f74d82cdf8c9213324313d52b23d28/.github/workflows/build.yml#L17-L27 - `macos-13` is deprecated and will disappear in December. There is `macos-15-intel` if one wants to test on x86 rather than arm. - GHCs 9.2.4 and 9.4.3 are deprecated, relevant are 9.2.8 and 9.4.8. - Maybe more recent GHC versions are included. - Are there specific reasons to test on LTSs 15.3 (GHC 8.8.2), 17.5 (GHC 8.10.4), and 22.7 (GHC 9.6.4) rather than 16.31 (GHC 8.8.4), 18.28 (GHC 8.10.7) and 22.44 (GHC 9.6.7)---the latter ones are the final ones in each series.