Update Exclusion Match Variable enum to support new values (Azure#16124)

Author: tejasshah7

specification/network/resource-manager/Microsoft.Network/stable/2021-05-01/examples/WafPolicyCreateOrUpdate.json

@@ -13,6 +13,18 @@
               "ruleSetType": "OWASP",
               "ruleSetVersion": "3.2"
             }
+          ],
+          "exclusions": [
+            {
+              "matchVariable": "RequestArgNames",
+              "selectorMatchOperator": "StartsWith",
+              "selector": "hello"
+            },
+            {
+              "matchVariable": "RequestArgValues",
+              "selectorMatchOperator": "StartsWith",
+              "selector": "test"
+            }
           ]
         },
         "customRules": [
@@ -100,6 +112,18 @@
                 "ruleSetType": "OWASP",
                 "ruleSetVersion": "3.2"
               }
+            ],
+            "exclusions": [
+              {
+                "matchVariable": "RequestArgNames",
+                "selectorMatchOperator": "StartsWith",
+                "selector": "hello"
+              },
+              {
+                "matchVariable": "RequestArgValues",
+                "selectorMatchOperator": "StartsWith",
+                "selector": "test"
+              }
             ]
           },
           "customRules": [
@@ -190,6 +214,18 @@
                 "ruleSetType": "OWASP",
                 "ruleSetVersion": "3.2"
               }
+            ],
+            "exclusions": [
+              {
+                "matchVariable": "RequestArgNames",
+                "selectorMatchOperator": "StartsWith",
+                "selector": "hello"
+              },
+              {
+                "matchVariable": "RequestArgValues",
+                "selectorMatchOperator": "StartsWith",
+                "selector": "test"
+              }
             ]
           },
           "customRules": [

specification/network/resource-manager/Microsoft.Network/stable/2021-05-01/examples/WafPolicyGet.json

@@ -130,6 +130,11 @@
                 "matchVariable": "RequestHeaderNames",
                 "selectorMatchOperator": "StartsWith",
                 "selector": "testHeader2"
+              },
+              {
+                "matchVariable": "RequestArgValues",
+                "selectorMatchOperator": "StartsWith",
+                "selector": "hello"
               }
             ]
           }

specification/network/resource-manager/Microsoft.Network/stable/2021-05-01/webapplicationfirewall.json

@@ -708,7 +708,13 @@
           "enum": [
             "RequestHeaderNames",
             "RequestCookieNames",
-            "RequestArgNames"
+            "RequestArgNames",
+            "RequestHeaderKeys",
+            "RequestHeaderValues",
+            "RequestCookieKeys",
+            "RequestCookieValues",
+            "RequestArgKeys",
+            "RequestArgValues"
           ],
           "description": "The variable to be excluded.",
           "x-ms-enum": {