suggestion: `latestNightlyWith` argument `previous`: {major / minor / patch}

[valeratrades]

I have dozens of projects that bring cargo with

        rust = pkgs.rust-bin.selectLatestNightlyWith (toolchain: toolchain.default.override {
          extensions = [ "rust-src" "rust-analyzer" "rust-docs" "rustc-codegen-cranelift-preview" ];
        });

which runs into problems when multiple projects are opened simultaneously, as sccache is helpless as soon as cargo versions mismatch.

I suggest introducing either of:

previous: {minor / major / patch}

previous: "minor";

which is set to "minor" here, so with latest nightly today being cargo 1.92.0-nightly (81c3f77a4 2025-10-10), would get latest revision of 1.91.0

refresh: {monthly / weekly / daily }

refresh: weekly

which will pull the latest version, satisfying the requirements, before the last complete interval ({month / week / day} by UTC).
Making it more difficult for cargo versions to diverge across actively developed projects, the longer the configured interval is.

// can try to implement myself, if you're okay with including it