ci: Bump nixpkgs

ci/base-nixpkgs.nix

 # To update nixpkgs bump rev and baseNixpkgs's sha256.
 let
-  rev = "c2fd152c98dc618c9c06b1551faee17e79a03b7f";
+  rev = "6ec10fc77e56b9f848930f129833cfbbac736e4f";
 in
 fetchTarball {
   url = "https://github.com/NixOS/nixpkgs/archive/${rev}.tar.gz";
-  sha256 = "07cafslsgdymzcfcpgzw8fqv07r4wslsz7xijni1l1n2agcj2436";
+  sha256 = "196nhr6dcwc2v6aansw74vaqznpq3p4qfrlqv12lplnzwyfhyxxc";
 }