SwaggerStartupMultipeDoc.cs

services.AddSwaggerGen(c =>
{
    c.SwaggerDoc("v1", new Info
    {
        Version = "v1",
        Title = "My API",
        Description = "My First ASP.NET Core Web API",
        Contact = new Contact() { Name = "Talking Dotnet", Email = "contact@talkingdotnet.com", Url = "www.talkingdotnet.com" }
    });

    c.SwaggerDoc("v2", new Info
    {
        Version = "v2",
        Title = "New API",
        Description = "Sample Web API",
        Contact = new Contact() { Name = "Talking Dotnet", Email = "contact@talkingdotnet.com", Url = "www.talkingdotnet.com" }
    });
});