nixos/upower: update percentage defaults

Current defaults were added in aecfea0, which were in turn based on upstream:
https://gitlab.freedesktop.org/upower/upower/-/blob/28bd86c181e2510ef6a1dc7cfa26f97803698a79/etc/UPower.conf.

Current upstream config:
https://gitlab.freedesktop.org/upower/upower/-/blob/94c91f93f133e23da25a9a7be57db745a30dc5f1/etc/UPower.conf

nixos/modules/services/hardware/upower.nix

@@ -85,7 +85,7 @@ in
 
       percentageLow = lib.mkOption {
         type = lib.types.ints.unsigned;
-        default = 10;
+        default = 20;
         description = ''
           When `usePercentageForPolicy` is
           `true`, the levels at which UPower will consider the
@@ -103,7 +103,7 @@ in
 
       percentageCritical = lib.mkOption {
         type = lib.types.ints.unsigned;
-        default = 3;
+        default = 5;
         description = ''
           When `usePercentageForPolicy` is
           `true`, the levels at which UPower will consider the