[ReleasePR sql] Change SecurityAlertPolicyName from default to Default (#1882)

Create to sync Azure/azure-rest-api-specs#15750
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...AzureSDKAutomation:sdkAuto/sql?expand=1)

Author: msftbot[bot]

schemas/2020-11-01-preview/Microsoft.Sql.json

@@ -587,7 +587,7 @@
           "oneOf": [
             {
               "type": "string",
-              "pattern": "^.*/default$"
+              "pattern": "^.*/Default$"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -950,7 +950,7 @@
           "oneOf": [
             {
               "type": "string",
-              "pattern": "^.*/default$"
+              "pattern": "^.*/Default$"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -1783,7 +1783,7 @@
           "oneOf": [
             {
               "type": "string",
-              "pattern": "^.*/default$"
+              "pattern": "^.*/Default$"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -2852,7 +2852,7 @@
           "oneOf": [
             {
               "type": "string",
-              "pattern": "^.*/default$"
+              "pattern": "^.*/Default$"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -5490,7 +5490,7 @@
         "name": {
           "type": "string",
           "enum": [
-            "default"
+            "Default"
           ],
           "description": "The name of the security alert policy."
         },
@@ -5736,7 +5736,7 @@
         "name": {
           "type": "string",
           "enum": [
-            "default"
+            "Default"
           ],
           "description": "The name of the security alert policy."
         },
@@ -7044,7 +7044,7 @@
         "name": {
           "type": "string",
           "enum": [
-            "default"
+            "Default"
           ],
           "description": "The name of the security alert policy."
         },
@@ -7989,7 +7989,7 @@
         "name": {
           "type": "string",
           "enum": [
-            "default"
+            "Default"
           ],
           "description": "The name of the threat detection policy."
         },

schemas/2021-02-01-preview/Microsoft.Sql.json

@@ -587,7 +587,7 @@
           "oneOf": [
             {
               "type": "string",
-              "pattern": "^.*/default$"
+              "pattern": "^.*/Default$"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -950,7 +950,7 @@
           "oneOf": [
             {
               "type": "string",
-              "pattern": "^.*/default$"
+              "pattern": "^.*/Default$"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -1835,7 +1835,7 @@
           "oneOf": [
             {
               "type": "string",
-              "pattern": "^.*/default$"
+              "pattern": "^.*/Default$"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -2942,7 +2942,7 @@
           "oneOf": [
             {
               "type": "string",
-              "pattern": "^.*/default$"
+              "pattern": "^.*/Default$"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -5612,7 +5612,7 @@
         "name": {
           "type": "string",
           "enum": [
-            "default"
+            "Default"
           ],
           "description": "The name of the security alert policy."
         },
@@ -5858,7 +5858,7 @@
         "name": {
           "type": "string",
           "enum": [
-            "default"
+            "Default"
           ],
           "description": "The name of the security alert policy."
         },
@@ -7239,7 +7239,7 @@
         "name": {
           "type": "string",
           "enum": [
-            "default"
+            "Default"
           ],
           "description": "The name of the security alert policy."
         },
@@ -8222,7 +8222,7 @@
         "name": {
           "type": "string",
           "enum": [
-            "default"
+            "Default"
           ],
           "description": "The name of the threat detection policy."
         },