fix maxcolwidths doesn't accept tuple

Author: Racerroar888

README.md

@@ -1123,5 +1123,5 @@ Bart Broere, Vilhelm Prytz, Alexander Gažo, Hugo van Kemenade,
 jamescooke, Matt Warner, Jérôme Provensal, Kevin Deldycke,
 Kian-Meng Ang, Kevin Patterson, Shodhan Save, cleoold, KOLANICH,
 Vijaya Krishna Kasula, Furcy Pin, Christian Fibich, Shaun Duncan,
-Dimitri Papadopoulos.
+Dimitri Papadopoulos, Racerroar.
 

tabulate/__init__.py

@@ -2071,6 +2071,8 @@ def tabulate(
     list_of_lists, separating_lines = _remove_separating_lines(list_of_lists)
 
     if maxcolwidths is not None:
+        if type(maxcolwidths) is tuple:  # Check if tuple, convert to list if so
+            maxcolwidths = list(maxcolwidths)
         if len(list_of_lists):
             num_cols = len(list_of_lists[0])
         else: