Update templates to support the new pattern used for integration tests

[javiercn]

I tried running the EF tools with both patterns to verify that they both work. Below is the output

C:\work\template-tests\pattern> cat .\Program.cs
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;

namespace pattern
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateWebHostBuilder(args).Build().Run();
        }

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>();
    }
}

C:\work\template-tests\pattern> dotnet ef migrations list
info: Microsoft.AspNetCore.DataProtection.KeyManagement.XmlKeyManager[0]
      User profile is available. Using 'C:\Users\jacalvar\AppData\Local\ASP.NET\DataProtection-Keys' as key repository and Windows DPAPI to encrypt keys at rest.
info: Microsoft.EntityFrameworkCore.Infrastructure[10403]
      Entity Framework Core 2.1.0-preview1-27373 initialized 'ApplicationDbContext' using provider 'Microsoft.EntityFrameworkCore.Sqlite' with options: None
00000000000000_CreateIdentitySchema

C:\work\template-tests\pattern> code . .\Program.cs

C:\work\template-tests\pattern> cat .\Program.cs
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;

namespace pattern
{
    public class Program
    {
        public static void Main(string[] args)
        {
            BuildWebHost(args).Run();
        }

        public static IWebHost BuildWebHost(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>()
                .Build();
    }
}

C:\work\template-tests\pattern> dotnet ef migrations list
info: Microsoft.AspNetCore.DataProtection.KeyManagement.XmlKeyManager[0]
      User profile is available. Using 'C:\Users\jacalvar\AppData\Local\ASP.NET\DataProtection-Keys' as key repository and Windows DPAPI to encrypt keys at rest.
info: Microsoft.EntityFrameworkCore.Infrastructure[10403]
      Entity Framework Core 2.1.0-preview1-27373 initialized 'ApplicationDbContext' using provider 'Microsoft.EntityFrameworkCore.Sqlite' with options: None
00000000000000_CreateIdentitySchema
```

[dnfclas]

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[Eilon]

Per my understanding of what this ought to look like, this is good.

[ajcvickers]

Won't this break EF tooling? /cc @bricelam

[Eilon]

I believe EF tooling was updated by @javiercn .

[Eilon]

dotnet/efcore#10100

[ajcvickers]

Okay, so EF tooling now supports both patterns? So, this change will work with EF Core 2.1, but not with 2.0, but an app created using the 2.0 pattern will continue to work with 2.1? If so, I think that's okay.

[javiercn]

Yep

[Eilon]

Oh actually, do the SPA templates need to be updated? E.g. https://github.com/aspnet/templating/blob/dev/src/Microsoft.DotNet.Web.Spa.ProjectTemplates/content/Angular-CSharp/Program.cs#L15-L23

cc @SteveSandersonMS

[SteveSandersonMS]

@Eilon Any changes to the .NET parts of the project templates should be applied to the SPA ones at the same time, yes.

[javiercn]

@SteveSandersonMS I've updated the spa templates with the new pattern.
@Eilon I've also updated the F# templates.

[Eilon]

Very... nice?? 😄