flake.lock: Update

Flake lock file updates:

• Updated input 'advisory-db':
    'github:rustsec/advisory-db/0631800c0a23c1e543842a70ccb698d0690f8cc3' (2024-04-13)
  → 'github:rustsec/advisory-db/6ab370c779c140c9cb2e7ff1367dd1b66c415409' (2024-04-20)
• Updated input 'crane':
    'github:ipetkov/crane/220387ac8e99cbee0ca4c95b621c4bc782b6a235' (2024-04-09)
  → 'github:ipetkov/crane/45ea0059fb325132fdc3c39faffb0941d25d08d3' (2024-04-18)
• Updated input 'fenix':
    'github:nix-community/fenix/c739f83545e625227f4d0af7fe2a71e69931fa4c' (2024-04-12)
  → 'github:nix-community/fenix/3247290e1bba55878a2c62d43894d0309d29c918' (2024-04-20)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/657b33b0cb9bd49085202e91ad5b4676532c9140' (2024-04-11)
  → 'github:rust-lang/rust-analyzer/c83d8cf5844fff3d6e243ab408669222059af1c6' (2024-04-19)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/a0c9e3aee1000ac2bfb0e5b98c94c946a5d180a9' (2024-04-12)
  → 'github:nixos/nixpkgs/fd16bb6d3bcca96039b11aa52038fafeb6e4f4be' (2024-04-20)