The error which I am facing –

PM> update-database
Build started…
Build succeeded.
An error occurred while accessing the Microsoft.Extensions.Hosting services. Continuing without the application service provider. Error: Failed to load configuration from file ‘C:UsersshubhsourcereposProjectOneappsettings.json’.
Unable to create a ‘DbContext’ of type ”. The exception ‘Unable to resolve service for type ‘Microsoft.EntityFrameworkCore.DbContextOptions`1[ProjectOne.Data.ApplicationContext]’ while attempting to activate ‘ProjectOne.Data.ApplicationContext’.’ was thrown while attempting to create an instance. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728
PM>

ApplicationContext.cs –

using Microsoft.EntityFrameworkCore;
using ProjectOne.Models;
namespace ProjectOne.Data

{
    public class ApplicationContext : DbContext
    {
    public ApplicationContext(DbContextOptions<ApplicationContext> options):base(options) { }
    public DbSet<Employee> Employees { get; set; }
    public DbSet<Department> Departments { get; set; }
    }
}

appsettings.json –

{
  {
    "ConnectionStrings": {
      "ProductionDB": "Data Source=DESKTOP-R6LR1KA\SQLEXPRESS;Initial Catalog=MultiTable;Integrated Security=True;Trust Server Certificate=True"
    },
    "Logging": {
      "LogLevel": {
        "Default": "Information",
        "Microsoft.AspNetCore": "Warning"
      }
    },
    "AllowedHosts": "*"
  }

Program.cs –

using Microsoft.EntityFrameworkCore;
using ProjectOne.Data;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddControllersWithViews();
builder.Services.AddDbContext<ApplicationContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("ProductionDB")));

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();

app.UseAuthorization();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

app.Run();

I have installed Entity FrameWork Tools, CORE, Design as well.
Its not working still hope u fix it up .. I am using 8.0.7 latest ones