Update stackage and nixpkgs version used by haskell.nix.

nix/default.nix

@@ -21,7 +21,7 @@ let
     # haskell.nix provides access to the nixpkgs pins which are used by our CI,
     # hence you will be more likely to get cache hits when using these.
     # But you can also just use your own, e.g. '<nixpkgs>'.
-    haskellNix.sources.nixpkgs-2009
+    haskellNix.sources.nixpkgs-2105
     # These arguments passed to nixpkgs, include some patches and also
     # the haskell.nix functionality itself as an overlay.
     (haskellNix.nixpkgsArgs // { overlays = allOverlays; });

nix/materialized.paymentserver/default.nix

@@ -9,7 +9,7 @@
         servant-prometheus = ./.stack-to-nix.cache.0;
         };
       };
-  resolver = "lts-14.1";
+  resolver = "lts-14.2";
   modules = [
     ({ lib, ... }:
       { packages = {}; })

stack.yaml

@@ -17,7 +17,7 @@
 #
 # resolver: ./custom-snapshot.yaml
 # resolver: https://example.com/snapshots/2018-01-01.yaml
-resolver: lts-14.1
+resolver: lts-14.2
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.