[s360 fix] add default value to $.properties.template.scale.maxReplicas (#21264)

to fix https://portal.azure-devex-tools.com/amekpis/correctness/detail?errorId=CCE1B9E9-6969-430D-A682-03A86292EDFD

Co-authored-by: Nan Jiang <[email protected]>

Author: najian

specification/app/resource-manager/Microsoft.App/preview/2022-01-01-preview/CommonDefinitions.json

@@ -391,7 +391,8 @@
         "maxReplicas": {
           "format": "int32",
           "description": "Optional. Maximum number of container replicas. Defaults to 10 if not set.",
-          "type": "integer"
+          "type": "integer",
+          "default": 10
         },
         "rules": {
           "description": "Scaling rules.",

specification/app/resource-manager/Microsoft.App/preview/2022-06-01-preview/CommonDefinitions.json

@@ -485,7 +485,8 @@
         "maxReplicas": {
           "format": "int32",
           "description": "Optional. Maximum number of container replicas. Defaults to 10 if not set.",
-          "type": "integer"
+          "type": "integer",
+          "default": 10
         },
         "rules": {
           "description": "Scaling rules.",