nsncd: add --version-regex to updateScript

Upstream tagged a .1.5.2 version (with a trailing dot), and r-ryantm
keeps sending PRs to bump to that.

Set --version-regex of nix-update-script to hopefully prevent it from
doing this.

See https://github.com/twosigma/nsncd/issues/202
See https://github.com/NixOS/nixpkgs/pull/518824
Closes https://github.com/NixOS/nixpkgs/pull/524808

pkgs/by-name/ns/nsncd/package.nix

@@ -56,6 +56,6 @@ rustPlatform.buildRustPackage {
 
   passthru = {
     tests.nscd = nixosTests.nscd;
-    updateScript = nix-update-script { };
+    updateScript = nix-update-script { extraArgs = [ "--version-regex=^v([0-9][0-9.]+)$" ]; };
   };
 }