fix: serialize Kafka schemaIdLocation with correct casing

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Author: bielu

src/ByteBard.AsyncAPI/Models/AsyncApiConstants.cs

@@ -119,7 +119,7 @@ public static class AsyncApiConstants
         public const string Method = "method";
         public const string SchemaIdPayloadEncoding = "schemaIdPayloadEncoding";
         public const string SchemaLookupStrategy = "schemaLookupStrategy";
-        public const string SchemaIdLocation = "SchemaIdLocation";
+        public const string SchemaIdLocation = "schemaIdLocation";
         public const string Query = "query";
         public const string GroupId = "groupId";
         public const string ClientId = "clientId";

test/ByteBard.AsyncAPI.Tests/Bindings/Kafka/KafkaBindings_Should.cs

@@ -117,7 +117,7 @@ public void V2_KafkaMessageBinding_WithFilledObject_SerializesAndDeserializes()
                   kafka:
                     key:
                       description: this mah other binding
-                    SchemaIdLocation: test
+                    schemaIdLocation: test
                     schemaIdPayloadEncoding: test
                     schemaLookupStrategy: header
                 """;