flake.lock: Update

Flake lock file updates:

• Updated input 'fenix':
    'https://api.flakehub.com/f/pinned/nix-community/fenix/0.1.2542%2Brev-78d518f5ca32a86dc767de481160dbae640c70cf/019c1851-0ed1-7f81-b175-8e8bbad651e6/source.tar.gz' (2026-02-01)
  → 'https://api.flakehub.com/f/pinned/nix-community/fenix/0.1.2572%2Brev-47c5355eaba0b08836e720d5d545c8ea1e1783db/019ca881-cb35-7cd1-8b46-98117609f8b6/source.tar.gz' (2026-03-01)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/17304e9' (2026-01-31)
  → 'github:rust-lang/rust-analyzer/a96b6a9' (2026-02-28)
• Updated input 'nixpkgs':
    'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.953160%2Brev-2fc6539b481e1d2569f25f8799236694180c0993/019c8e05-d2f6-7c7e-9ead-612154b18bfb/source.tar.gz' (2026-02-23)
  → 'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.962836%2Brev-c06b4ae3d6599a672a6210b7021d699c351eebda/019cec4e-dd38-75a8-9d2d-0d91492115c9/source.tar.gz' (2026-03-13)

Author: github-actions[bot]