clickhouse: 20.11.4.13-stable -> 21.3.11.5-lts

Failing Hydra build: https://hydra.nixos.org/build/143269865
ZHF #122042

nixos/modules/services/databases/clickhouse.nix

@@ -42,6 +42,7 @@ with lib;
         User = "clickhouse";
         Group = "clickhouse";
         ConfigurationDirectory = "clickhouse-server";
+        AmbientCapabilities = "CAP_SYS_NICE";
         StateDirectory = "clickhouse";
         LogsDirectory = "clickhouse";
         ExecStart = "${pkgs.clickhouse}/bin/clickhouse-server --config-file=${pkgs.clickhouse}/etc/clickhouse-server/config.xml";

nixos/tests/clickhouse.nix

@@ -4,6 +4,7 @@ import ./make-test-python.nix ({ pkgs, ... }: {
 
   machine = {
     services.clickhouse.enable = true;
+    virtualisation.memorySize = 4096;
   };
 
   testScript =