flake.lock: Update (#448)

Flake lock file updates:

• Updated input 'neovim-nightly':
    'github:nix-community/neovim-nightly-overlay/d05e1d754812bcd89925d845992f377faf6c4944?narHash=sha256-Ru%2B5fwMqXEoc6G1PbuTppAzxtqvj0322cBAWCb0Yhbo%3D' (2024-12-26)
  → 'github:nix-community/neovim-nightly-overlay/7f5ed8f34dbb092799ac490d1235be0513646dba?narHash=sha256-1Mhdqza7WIdExqoeVWOLOZKM0qd/0mv137ScLrsk73A%3D' (2024-12-29)
• Updated input 'neovim-nightly/neovim-src':
    'github:neovim/neovim/487c48ec8689b865bad04fdb87b61f5ada25da97?narHash=sha256-ndlWdGm61W3uObi8cowWqnPdJwq2FsH4GHGOQYeNSOM%3D' (2024-12-25)
  → 'github:neovim/neovim/2b07b14eacf3197754c63f42f9c880e85960eef2?narHash=sha256-e1KLj%2B283Znt14U9DkKw%2BzPqShe0AkFPGpT44BhZ9KU%3D' (2024-12-28)
• Updated input 'neovim-nightly/nixpkgs':
    'github:NixOS/nixpkgs/de1864217bfa9b5845f465e771e0ecb48b30e02d?narHash=sha256-Ucfnxq1rF/GjNP3kTL%2BuTfgdoE9a3fxDftSfeLIS8mA%3D' (2024-12-23)
  → 'github:NixOS/nixpkgs/7cc0bff31a3a705d3ac4fdceb030a17239412210?narHash=sha256-7QEFnKkzD13SPxs%2BUFR5bUFN2fRw%2BGlL0am72ZjNre4%3D' (2024-12-27)

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