Remove broken wheel check in setup.py [ci skip]

setup.py

@@ -61,9 +61,6 @@ if sys.argv[-1] == 'publish':
         import pypandoc
     except ImportError:
         print("pypandoc not installed.\nUse `pip install pypandoc`.\nExiting.")
-    if os.system("pip freeze | grep wheel"):
-        print("wheel not installed.\nUse `pip install wheel`.\nExiting.")
-        sys.exit()
     if os.system("pip freeze | grep twine"):
         print("twine not installed.\nUse `pip install twine`.\nExiting.")
         sys.exit()