convert pre-commit-config.yaml from JSON to YAML

[peterbecich]

using https://www.geeksforgeeks.org/json-to-yaml-converter/ .

The new YAML configuration appears to be fine:

$ pre-commit run --all-files
stylish-haskell..........................................................Passed
mixed line ending........................................................Passed

This matches the standard YAML config of the tool: https://pre-commit.com/#installation

---

However, I am not certain .pre-commit-config.yaml is working as intended, on master or this PR. Can I fix this in a separate PR?

After putting some spaces into Experiments.hs

module Experiments
( Bench(..)
, BenchRun(..)
, Config(..)


, Verbosity(..)
...
import           Data.Either                        (fromRight)

import           Data.List
import           Data.Maybe
...

$ pre-commit run --all-files
stylish-haskell..........................................................Passed
mixed line ending........................................................Passed

pre-commit succeeds on master branch with the JSON configuration.

[fendor]

LGTM, I don't have any strong feelings here, since I am not using the pre-commit hook any way 🙊