[ci skip] Increase Drone CI resource quota to handle concurrent builds

Each build pod has 8-10 containers inheriting 1 CPU / 2Gi limits from
LimitRange defaults. With 4+ concurrent builds the old quota (48 CPU /
96Gi / 30 pods) was exhausted, blocking new builds. Increase to 64 CPU /
128Gi / 60 pods to safely support 5-6 concurrent builds.

modules/kubernetes/drone/main.tf

@@ -33,9 +33,9 @@ resource "kubernetes_resource_quota" "drone" {
     hard = {
       "requests.cpu"    = "16"
       "requests.memory" = "16Gi"
-      "limits.cpu"      = "48"
-      "limits.memory"   = "96Gi"
-      pods              = "30"
+      "limits.cpu"      = "64"
+      "limits.memory"   = "128Gi"
+      pods              = "60"
     }
   }
 }