services: nextcloud: bump to 31

Flake lock file updates:

• Updated input 'nixos-hardware':
    'github:NixOS/nixos-hardware/4602f7e1d3f197b3cb540d5accf5669121629628' (2025-06-06)
  → 'github:NixOS/nixos-hardware/61837d2a33ccc1582c5fabb7bf9130d39fee59ad' (2025-06-16)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/88331c17ba434359491e8d5889cce872464052c2' (2025-06-09)
  → 'github:NixOS/nixpkgs/9ba04bda9249d5d5e5238303c9755de5a49a79c5' (2025-06-18)

flake.lock

@@ -234,11 +234,11 @@
     },
     "nixos-hardware": {
       "locked": {
-        "lastModified": 1749195551,
-        "narHash": "sha256-W5GKQHgunda/OP9sbKENBZhMBDNu2QahoIPwnsF6CeM=",
+        "lastModified": 1750083401,
+        "narHash": "sha256-ynqbgIYrg7P1fAKYqe8I/PMiLABBcNDYG9YaAP/d/C4=",
         "owner": "NixOS",
         "repo": "nixos-hardware",
-        "rev": "4602f7e1d3f197b3cb540d5accf5669121629628",
+        "rev": "61837d2a33ccc1582c5fabb7bf9130d39fee59ad",
         "type": "github"
       },
       "original": {
@@ -298,11 +298,11 @@
     },
     "nixpkgs_3": {
       "locked": {
-        "lastModified": 1749494155,
-        "narHash": "sha256-FG4DEYBpROupu758beabUk9lhrblSf5hnv84v1TLqMc=",
+        "lastModified": 1750259320,
+        "narHash": "sha256-H8J4H2XCIMEJ5g6fZ179QfQvsc2dUqhqfBjC8RAHNRY=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "88331c17ba434359491e8d5889cce872464052c2",
+        "rev": "9ba04bda9249d5d5e5238303c9755de5a49a79c5",
         "type": "github"
       },
       "original": {

services/nextcloud.nix

@@ -62,7 +62,7 @@ in {
 
       hostName = "cloud.${domain}";
       https = true;
-      package = pkgs.nextcloud30;
+      package = pkgs.nextcloud31;
 
       maxUploadSize = "1G";