Can't migrate?

Question

ASP.NET

public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();
            string conString = Configuration["ConnectionStrings:DefaultConnection"];
            services.AddDbContext<DataContext>(options =>
            options.UseSqlServer(conString));
        }

public class DataContext : DbContext
    {
        public DataContext(DbContextOptions<DataContext> options) : base(options) { }
        public DbSet<GuestResponse> Responses { get; set; }

    }

public class HomeController : Controller
    {
        private DataContext context;
        public HomeController(DataContext ctx) => context = ctx;
        public IActionResult Index() => View();
        public IActionResult Respond() => View();

        [HttpPost]
        public IActionResult Respond(GuestResponse response)
        {
            context.Responses.Add(response);
            context.SaveChanges();
            return RedirectToAction(nameof(Thanks),
                new { Name = response.Name, WillAttend = response.WillAttend });
        }
        public IActionResult Thanks(GuestResponse response) => View(response);
        public IActionResult ListResponses() =>
            View(context.Responses.OrderByDescending(r => r.WillAttend));

    }

<Project Sdk="Microsoft.NET.Sdk.Web">
      <PropertyGroup>
        <TargetFramework>net5.0</TargetFramework>
      </PropertyGroup>
      <ItemGroup>
        <Folder Include="wwwroot\" />
      </ItemGroup>
  
        <ItemGroup>
        <PackageReference Include="Microsoft.EntityFrameworkCore" Version="5.0.5" />

        <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools" Version="5.0.5">
          <PrivateAssets>all</PrivateAssets>
          <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
        </DotNetCliToolReference>

        <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="5.0.5" />

        <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer.Design" Version="1.1.6" />

        <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="5.0.0" />
    
        <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="5.0.2" />
        </ItemGroup>
</Project>