flake.lock: Update (#266)

Flake lock file updates:

• Updated input 'neovim-nightly':
    'github:nix-community/neovim-nightly-overlay/60a8a1b221308566c51aa9a66e11145a3f141fc8?narHash=sha256-XlFgIhunVheMVT5hv%2BOv7wkjFldqqOWsRleYQHrgWQY%3D' (2024-06-11)
  → 'github:nix-community/neovim-nightly-overlay/84299e229226207721e142246ff8343f8a8c6e5d?narHash=sha256-7jIX4cUdn6LYP4l38S38nsSNbGMF5eXP9qKe69SR02k%3D' (2024-06-13)
• Updated input 'neovim-nightly/neovim-src':
    'github:neovim/neovim/37bf4c572a8fa20dc4a8433524ecc8c8d68fe53c?narHash=sha256-npcA3yWucHF5uKKqcrSLJAy0hk3tTxfVCo/Da/Z4OOM%3D' (2024-06-10)
  → 'github:neovim/neovim/53afdf360cf195c02c22865f4e63b273d1ef152e?narHash=sha256-hZYLBealuoS3bL3eXFeQVAoasThqf7DDwg8kW0ASTOE%3D' (2024-06-12)
• Updated input 'neovim-nightly/nixpkgs':
    'github:NixOS/nixpkgs/3bcedce9f4de37570242faf16e1e143583407eab?narHash=sha256-WMU6ZRZrBgEUDIF0siu2aIyVAXcxfElSwzZtS/mSpN4%3D' (2024-06-09)
  → 'github:NixOS/nixpkgs/e913ae340076bbb73d9f4d3d065c2bca7caafb16?narHash=sha256-Ds1QpobBX2yoUDx9ZruqVGJ/uQPgcXoYuobBguyKEh8%3D' (2024-06-11)

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