ci: add 6.8.1

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1732014248,
-        "narHash": "sha256-y/MEyuJ5oBWrWAic/14LaIr/u5E0wRVzyYsouYY3W6w=",
+        "lastModified": 1736012469,
+        "narHash": "sha256-/qlNWm/IEVVH7GfgAIyP6EsVZI6zjAx1cV5zNyrs+rI=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "23e89b7da85c3640bbc2173fe04f4bd114342367",
+        "rev": "8f3e1f807051e32d8c95cd12b9b421623850a34d",
         "type": "github"
       },
       "original": {