Update flake inputs (#133)

* flake.lock: Update

Flake lock file updates:

• Updated input 'agenix':
    'github:ryantm/agenix/e64961977f60388dd0b49572bb0fc453b871f896' (2023-03-31)
  → 'github:ryantm/agenix/2994d002dcff5353ca1ac48ec584c7f6589fe447' (2023-04-21)
• Updated input 'crane':
    'github:ipetkov/crane/0c9f468ff00576577d83f5019a66c557ede5acf6' (2023-04-11)
  → 'github:ipetkov/crane/54b63c8eae4c50172cb50b612946ff1d2bc1c75c' (2023-04-16)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/abe7316dd51a313ce528972b104f4f04f56eefc4' (2023-04-14)
  → 'github:nixos/nixpkgs/645bc49f34fa8eff95479f0345ff57e55b53437e' (2023-04-19)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/b6f8d87208336d7cb85003b2e439fc707c38f92a' (2023-04-15)
  → 'github:oxalica/rust-overlay/2c417c0460b788328220120c698630947547ee83' (2023-04-22)

* Cargo.lock: Update