How to add a custom header parameter at the end of the parameters list in Swagger 2.0/OpenAPI 3.0?

[alexpantyukhin]

I want to have my custom parameter at the end of parameters list in the swagger.json.
The example what I want to see:

        "parameters": [
          {
            "in": "path",
            "name": "Id",
            "required": true,
            "type": "integer",
            "format": "int32"
          },
          {
            "in": "body",
            "name": "body",
            "schema": {
              "type": "array",
              "items": {
                "$ref": "#/definitions/MyCustomClass"
              }
            }
          },
          {
            "in": "header",
            "name": "key",
            "description": "The key.",
            "type": "string"
          },
        ],

I used the following code :
in Program.cs:

   app.UseSwagger(p => p.SerializeAsV2 = true);

public class AddRequiredParameter: IOperationFilter
{
    public void Apply(OpenApiOperation operation, OperationFilterContext context)
    {
            var stringOpenApiSchema = context.SchemaGenerator.GenerateSchema(typeof(string), context.SchemaRepository);
            operation.Parameters.Add(new OpenApiParameter
            {
                Name = "key",
                In = ParameterLocation.Header,
                Schema = stringOpenApiSchema,
                Required = false,
                Description = "The key."
            });
            operation.Security = new List<OpenApiSecurityRequirement>();
    }
}

But now I have only the key parameter is placed before the body parameter:

        "parameters": [
          {
            "in": "path",
            "name": "Id",
            "required": true,
            "type": "integer",
            "format": "int32"
          },
          {
            "in": "header",
            "name": "key",
            "description": "The key.",
            "type": "string"
          },
          {
            "in": "body",
            "name": "body",
            "schema": {
              "type": "array",
              "items": {
                "$ref": "#/definitions/MyCustomClass"
              }
            }
          }
        ],

The problem I have is that the client's code generator changes the order of parameters because I used an old implementation of Swashbuckle for .NET 4.8, which placed the key parameter at the end.
Now, I just want to preserve as much as possible and maintain the same order of parameters.