flake: update inputs (#363)

Flake lock file updates:

• Updated input 'nixpkgs-stable':
    'github:NixOS/nixpkgs/23cbb250f3bf4f516a2d0bf03c51a30900848075?narHash=sha256-8fnFlXBgM/uSvBlLWjZ0Z0sOdRBesyNdH0%2BesxqizGc%3D' (2024-09-22)
  → 'github:NixOS/nixpkgs/babc25a577c3310cce57c72d5bed70f4c3c3843a?narHash=sha256-nPyrcFm6FSk7CxzVW4x2hu62aLDghNcv9dX6DF3dXw8%3D' (2024-09-23)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/2e19799819104b46019d339e78d21c14372d3666?narHash=sha256-uMZMjoCS2nf40TAE1686SJl3OXWfdfM%2BBDEfRdr%2BuLc%3D' (2024-09-24)
  → 'github:oxalica/rust-overlay/b5f76c3b09a8194889f5328a480fbea1a9115518?narHash=sha256-XLloPtQHKk/Tdt8t8zIb%2BJhmunlH3YB9Jz8RTlQ3N/4%3D' (2024-09-25)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>