chore: adopt Stack lts-19.11 (and GHC902), add Nix Shell

shell.nix

@@ -0,0 +1,19 @@
+{ pkgs ? import (fetchTarball https://github.com/NixOS/nixpkgs/archive/22.05.tar.gz) { }
+, ghcVersion ? "ghc902"
+, ...
+}:
+
+with pkgs;
+
+haskell.lib.buildStackProject rec {
+  name = "haspara-devshell";
+  src = ./.;
+  ghc = haskell.packages.${ghcVersion}.ghc;
+  buildInputs = [
+    haskell-language-server
+    haskellPackages.weeder
+    hlint
+    stack
+    stylish-haskell
+  ];
+}

stack-18.28.yaml

@@ -0,0 +1,14 @@
+resolver: lts-18.28
+
+packages:
+- .
+
+ghc-options:
+  "$locals": -fwrite-ide-info
+
+nix:
+  enable: true
+  shell-file: shell.nix
+  nix-shell-options:
+  - "--arg"
+  - "ghcVersion=ghc8107"

stack-18.28.yaml.lock

@@ -0,0 +1,12 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    sha256: 428ec8d5ce932190d3cbe266b9eb3c175cd81e984babf876b64019e2cbe4ea68
+    size: 590100
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/18/28.yaml
+  original: lts-18.28

stack.yaml

@@ -1,5 +1,14 @@
-resolver: lts-18.27
+resolver: lts-19.11
+
 packages:
 - .
+
 ghc-options:
   "$locals": -fwrite-ide-info
+
+nix:
+  enable: true
+  shell-file: shell.nix
+  nix-shell-options:
+  - "--arg"
+  - "ghcVersion=ghc902"

stack.yaml.lock

@@ -6,7 +6,7 @@
 packages: []
 snapshots:
 - completed:
-    size: 590102
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/18/27.yaml
-    sha256: 79a786674930a89301b0e908fad2822a48882f3d01486117693c377b8edffdbe
-  original: lts-18.27
+    sha256: 692668712aa3a6638401ce921cd043f5f9a8b018af9ba13ae350871196b047d6
+    size: 619152
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/19/11.yaml
+  original: lts-19.11