nix-prefetch fails: experimental Nix feature 'flakes' is disabled

https://github.com/m15a/flake-awesome-neovim-plugins/actions/runs/8952064248/job/24589055860#step:5:1952

update.fnl: extra hash (cargoSha256): github.com/michaelb/sniprun
warning: unknown setting 'upgrade-nix-store-path-url'
warning: unknown setting 'upgrade-nix-store-path-url'
error:
       … <borked>

         at «none»:0: (source not available)

       … in the left operand of the update (//) operator

         at /nix/store/dxrf39afi5ijvlyrfymjg3b18vqj7irn-nix-prefetch-0.4.1/lib/nix-prefetch/prelude.nix:3:46:

            2|
            3| let prelude = with prelude; import ./lib.nix // {
             |                                              ^
            4|   fetcher = if orig.fetcher == null || elem orig.fetcher.type [ "file" "attr" ]

       (stack trace truncated; use '--show-trace' to show the full trace)

       error: experimental Nix feature 'flakes' is disabled; use '--extra-experimental-features flakes' to override
Error: fnl: [ERROR] failed to run nix-prefetch

m15a / flake-awesome-neovim-plugins

nix-prefetch fails: experimental Nix feature 'flakes' is disabled #130