Update dependencies and documentation #673

Job	Run time
pkgs-linux: nixpkgs: build	2m 3s
pkgs-linux: nixpkgs: prebuilt	5m 10s
pkgs-linux: haskell-nix: build	55s
pkgs-linux: haskell-nix: prebuilt	55s
pkgs-linux: shajra: build	1m 42s
pkgs-linux: shajra: prebuilt	52s
installers-linux	15s
pkgs-darwin: nixpkgs: build	4m 16s
pkgs-darwin: nixpkgs: prebuilt	6m 27s
pkgs-darwin: haskell-nix: build	4m 58s
pkgs-darwin: haskell-nix: prebuilt	2m 33s
pkgs-darwin: shajra: build	2m 1s
pkgs-darwin: shajra: prebuilt	1m 53s
	34m 0s

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