Allow major upgrades in staging

Author: farski

spire/templates/apps/castle.yml

@@ -445,7 +445,7 @@ Resources:
     UpdateReplacePolicy: Retain
     Properties:
       AllocatedStorage: !If [IsProduction, "400", "100"]
-      AllowMajorVersionUpgrade: false
+      AllowMajorVersionUpgrade: !If [IsProduction, false, true]
       AutoMinorVersionUpgrade: false
       BackupRetentionPeriod: 7
       CopyTagsToSnapshot: true