Merge pull request #268110 from tyxieblub/squid-service

nixos/modules/services/networking/squid.nix

···
       serviceConfig = {
         PIDFile="/run/squid.pid";
         ExecStart  = "${cfg.package}/bin/squid --foreground -YCs -f ${squidConfig}";
-        ExecReload="kill -HUP $MAINPID";
+        ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
         KillMode="mixed";
         NotifyAccess="all";
       };