Update Nix code and plutus-apps dependency

This was surprisingly easy.

Author: L-as

cabal-haskell.nix.project

@@ -1,14 +1,9 @@
--- Bump this if you need newer packages
-index-state: 2021-10-20T00:00:00Z
+index-state: 2022-01-22T00:00:00Z
 
 packages: ./.
           ./examples/plutus-game/plutus-game.cabal
           ./examples/plutus-transfer/plutus-transfer.cabal
           ./examples/plutus-nft/plutus-nft.cabal
 
--- You never, ever, want this.
-write-ghc-environment-files: never
-
--- Always build tests and benchmarks.
 tests: true
 benchmarks: true