升级 core 3.0 后，无法在包管理器中添加迁移。这是我的错误
PM> Add-Migration UpdateAlertTable -Context OozymContext
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
---> System.TypeLoadException: Could not load type 'Microsoft.EntityFrameworkCore.Internal.ProductInfo' from assembly 'Microsoft.EntityFrameworkCore, Version=3.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'.
at Microsoft.EntityFrameworkCore.Design.OperationExecutor..ctor(Object reportHandler, IDictionary args)
--- End of inner exception stack trace ---
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture)
at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, …