chore(deps): update nixpkgs

nix/static.nix

@@ -25,9 +25,16 @@ let
 
       overrides = pkgs.lib.composeExtensions old.overrides (_: prev: {
         postgresql-libpq = (lib.overrideCabal prev.postgresql-libpq {
+          # TODO: This section can be simplified when this PR has made it's way to us:
+          #  https://github.com/NixOS/nixpkgs/pull/286370
+          # Additionally, we need to use the default version in nixpkgs, otherwise the
+          # override will not be active as well.
+          # Using use-pkg-config flag, because pg_config won't work when cross-compiling
+          configureFlags = [ "-fuse-pkg-config" ];
           # postgresql doesn't build in the fully static overlay - but the default
           # derivation is built with static libraries anyway.
           libraryPkgconfigDepends = [ pkgsCross.libpq ];
+          librarySystemDepends = [ ];
         }).overrideAttrs (_: prevAttrs: {
           buildInputs = prevAttrs.buildInputs ++ [ pkgsStatic.openssl ];
         });