Fixes based on PR feedback

Author: darrelmiller

src/Microsoft.OpenApi.Readers/V2/OpenApiHeaderDeserializer.cs

@@ -166,10 +166,6 @@ private static void LoadStyle(OpenApiHeader h, string v)
                     return;
                 case "tsv":
                     throw new NotSupportedException();
-                case "multi":
-                    h.Style = ParameterStyle.Form;
-                    h.Explode = true;
-                    return;
             }
         }
     }

test/Microsoft.OpenApi.Readers.Tests/V2Tests/OpenApiParameterTests.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license. 
 
+using System.Collections.Generic;
 using System.IO;
 using FluentAssertions;
 using Microsoft.OpenApi.Any;
@@ -145,11 +146,24 @@ public void ParseHeaderParameterShouldSucceed()
                         Items = new OpenApiSchema
                         {
                             Type = "integer",
-                            Format = "int64"
+                            Format = "int64",
+                            Enum = new List<IOpenApiAny>
+                            {
+                                new OpenApiInteger(1),
+                                new OpenApiInteger(2),
+                                new OpenApiInteger(3),
+                                new OpenApiInteger(4),
+                            }
                         },
                         Default = new OpenApiArray() {
                             new OpenApiInteger(1),
                             new OpenApiInteger(2)
+                        },
+                        Enum = new List<IOpenApiAny>
+                        {
+                            new OpenApiArray() { new OpenApiInteger(1), new OpenApiInteger(2) },
+                            new OpenApiArray() { new OpenApiInteger(2), new OpenApiInteger(3) },
+                            new OpenApiArray() { new OpenApiInteger(3), new OpenApiInteger(4) }
                         }
                     }
                 });

test/Microsoft.OpenApi.Readers.Tests/V2Tests/Samples/OpenApiParameter/headerParameter.yaml

@@ -8,4 +8,9 @@ default: [1,2]
 items:
   type: integer
   format: int64
-collectionFormat: csv
+  enum: [1,2,3,4]
+collectionFormat: csv
+enum: 
+  - [1,2]
+  - [2,3]
+  - [3,4]