Update a template after `nix flake new -t`

Hi! I made a template for Haskell and used it to create a directory: nix flake new -t github:br4ch1st0chr0n3/templates#haskell-hello ./haskell-hello. After that, I updated the code in the repository and made a directory again. The code didn’t change so I suspected nix cached this repo somewhere. How can I update this cache?

One can use nix flake lock github:...