FIX: C# 9 new feature (Top-level statements) invalidate Basics (needs to be updated)

Hey there,
Hope you be ok.

Starting in C# 9, there's no need to explicitly include a Main method in a console application project. Instead, we can use the top-level statements feature to minimize the code we have to write. In this case, the compiler generates a class and Main method entry point for the application.

Here's a Program.cs file that is a complete C# program in C# 10:

```csharp
Console.WriteLine("Hello World!");
```
The `Basics` concept file includes the statement _“C# is an object-oriented language and requires all functions to be defined in a class”_ which is not %100 true anymore. I recommend updating this file to include a hint for the new feature of the language so there be no mistakes in the text.

~ _Thank you for the great C# track, I'll be happy to fix this issue if that's needed._