Revert "Update to resolver 20.11"

[iHiD]

Reverts #72

[iHiD]

@ErikSchierboom Can you revert this revert tomorrow pls. This deploy caused the machines to run out of HDD space so I reverted it. Not anyone's fault (other than mine really) but reverting was the quickest solution. As a note, this image is huge though (5GB) compared to other that are like 200MB.

[MatthijsBlom]

This revert broke all exercises on the Haskell track again.

I guess this could (largely) be fixed by reverting exercism/haskell#1158 as well, but seeing as this one will be reverted tomorrow it's probably not worth the hassle. I'll post a heads-up on the forum.

[ErikSchierboom]

@MatthijsBlom Is there any way in which we can reduce the image size? In particular, we're running stack build --resolver lts-20.18 --no-terminal --test --no-run-tests beforehand to pre-compile/download any extra dependencies.

[MatthijsBlom]

I hardly know anything about what an image is, or what the test runner even does. I'd need to read up / be explained.

However,

In particular, we're running stack build --resolver lts-20.18 --no-terminal --test --no-run-tests beforehand to pre-compile/download any extra dependencies.

Do I understand correctly that you are 'pre-compiling' the allowed dependencies every time?

[ErikSchierboom]

No, we're precompiling them once when we build the image