Bump Nix/CI, drop support for GHC 8.10, and add support for GHC 9.4 and 9.6 #178

Job	Run time
Build - Windows	6m 1s
Build & Test - ubuntu-latest - stack.yaml	10m 21s
Build & Test - ubuntu-latest - stack-lts-18.yaml	21m 11s
Build & Test - ubuntu-latest - stack-lts-19.yaml	9m 53s
Build & Test - macos-latest - stack.yaml	19m 54s
Build & Test - macos-latest - stack-lts-18.yaml	14m 39s
Build & Test - macos-latest - stack-lts-19.yaml	20m 3s
	1h 42m 2s

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