flake.lock: Update

Flake lock file updates:

```
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/11415c7ae8539d6292f2928317ee7a8410b28bb9' (2025-02-21)
  → 'github:nixos/nixpkgs/b27ba4eb322d9d2bf2dc9ada9fd59442f50c8d7c' (2025-02-28)
• Updated input 'nixpkgs-unstable':
    'github:nixos/nixpkgs/73cf49b8ad837ade2de76f87eb53fc85ed5d4680' (2025-02-18)
  → 'github:nixos/nixpkgs/6313551cd05425cd5b3e63fe47dbc324eabb15e4' (2025-02-27)
```

flake.lock

@@ -20,11 +20,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1740463929,
-        "narHash": "sha256-4Xhu/3aUdCKeLfdteEHMegx5ooKQvwPHNkOgNCXQrvc=",
+        "lastModified": 1740743217,
+        "narHash": "sha256-brsCRzLqimpyhORma84c3W2xPbIidZlIc3JGIuQVSNI=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "5d7db4668d7a0c6cc5fc8cf6ef33b008b2b1ed8b",
+        "rev": "b27ba4eb322d9d2bf2dc9ada9fd59442f50c8d7c",
         "type": "github"
       },
       "original": {
@@ -36,11 +36,11 @@
     },
     "nixpkgs-unstable": {
       "locked": {
-        "lastModified": 1740367490,
-        "narHash": "sha256-WGaHVAjcrv+Cun7zPlI41SerRtfknGQap281+AakSAw=",
+        "lastModified": 1740695751,
+        "narHash": "sha256-D+R+kFxy1KsheiIzkkx/6L63wEHBYX21OIwlFV8JvDs=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "0196c0175e9191c474c26ab5548db27ef5d34b05",
+        "rev": "6313551cd05425cd5b3e63fe47dbc324eabb15e4",
         "type": "github"
       },
       "original": {