Update configuration files

Signed-off-by: Oliver Davies <oliver@oliverdavies.uk>

drupal-nix-flake/tools/nix/dev-shells.nix

@@ -0,0 +1,31 @@
+{ inputs, ... }:
+
+{
+  imports = [ inputs.devshell.flakeModule ];
+
+  perSystem =
+    { pkgs, ... }:
+    {
+      devshells.default =
+        with pkgs;
+        let
+          php = pkgs.php83.buildEnv {
+            extraConfig = ''
+              memory_limit = 128M
+            '';
+          };
+
+          phpPackages = pkgs.php83Packages;
+        in
+        {
+          packages = [
+            mariadb
+            php
+            phpPackages.composer
+            phpactor
+            pv
+            yamlfmt
+          ];
+        };
+    };
+}