How to turn off or handle camelCasing in JSON response ASP.NET Core?

For those who needs a solution about a PascalCase within Api Project that has not the Mvc services you should add this after AddControllers services

 // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers().AddJsonOptions(jsonOptions =>
                {
                    jsonOptions.JsonSerializerOptions.PropertyNamingPolicy = null;
                } ;
        }

In Asp.Net Core 3.0 some things have changed. For camelCase do nothing that is out of the box. For PascalCase or another set style use.

services.AddMvc(setupAction=> {
            setupAction.EnableEndpointRouting = false;
        }).AddJsonOptions(jsonOptions =>
        {
            jsonOptions.JsonSerializerOptions.PropertyNamingPolicy = null;
        })
        .SetCompatibilityVersion(CompatibilityVersion.Version_3_0);

In Startup.cs ConfigureServices section