Changing the name of a column doesn't change the name you use to access the column #5916

System Information (please complete the following information):

• OS & Version: [e.g. Windows 10]
• ML.NET Version: ML.NET 0.18.0
• .NET Version: .net Framework 4.8

Describe the bug
Changing the name of a column in a DataFrame doesn't change the name you use to access the column

To Reproduce
Steps to reproduce the behavior:

        StringDataFrameColumn city = new StringDataFrameColumn("City", new string[] { "London", "Berlin" });
        PrimitiveDataFrameColumn<int> temp = new PrimitiveDataFrameColumn<int>("Temperature", new int[] { 12, 13 });

        DataFrame dataframe = new DataFrame(city, temp);
        Console.WriteLine((string)dataframe["City"][0]);

        // Change the name of the column:
        dataframe["City"].SetName("Stadt");

        // Still accessed as "City" but is named Stadt 
        Console.WriteLine(dataframe["City"].Name);

        // Accessing as "Stadt" cause an exception
        Console.WriteLine((string)dataframe["Stadt"][0]);

Expected behavior
That the column name inside the DataFrame gets updated so it can be accessed as:
dataframe["new name"]

Additional context
Would be great if one could change the name of a column and get a new column where the name is new but it points to the same data. (Useful for my use case, and perhaps valuable for others too.)