flake.lock: Update

Flake lock file updates:

```
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/cdd2ef009676ac92b715ff26630164bb88fec4e0' (2025-03-13)
  → 'github:nixos/nixpkgs/7105ae3957700a9646cc4b766f5815b23ed0c682' (2025-03-20)
• Updated input 'nixpkgs-unstable':
    'github:nixos/nixpkgs/6607cf789e541e7873d40d3a8f7815ea92204f32' (2025-03-13)
  → 'github:nixos/nixpkgs/a84ebe20c6bc2ecbcfb000a50776219f48d134cc' (2025-03-19)
```

flake.lock

@@ -20,11 +20,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1741862977,
-        "narHash": "sha256-prZ0M8vE/ghRGGZcflvxCu40ObKaB+ikn74/xQoNrGQ=",
+        "lastModified": 1742512142,
+        "narHash": "sha256-8XfURTDxOm6+33swQJu/hx6xw1Tznl8vJJN5HwVqckg=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "cdd2ef009676ac92b715ff26630164bb88fec4e0",
+        "rev": "7105ae3957700a9646cc4b766f5815b23ed0c682",
         "type": "github"
       },
       "original": {
@@ -36,11 +36,11 @@
     },
     "nixpkgs-unstable": {
       "locked": {
-        "lastModified": 1741851582,
-        "narHash": "sha256-cPfs8qMccim2RBgtKGF+x9IBCduRvd/N5F4nYpU0TVE=",
+        "lastModified": 1742422364,
+        "narHash": "sha256-mNqIplmEohk5jRkqYqG19GA8MbQ/D4gQSK0Mu4LvfRQ=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "6607cf789e541e7873d40d3a8f7815ea92204f32",
+        "rev": "a84ebe20c6bc2ecbcfb000a50776219f48d134cc",
         "type": "github"
       },
       "original": {