start removal of six and improve type annotation (#607)

* fix unfinished Python2 -> 3 translation
* remove some six usage
* annotate
* fix regression in Six removal
* mypy: self.enf is always defined
* fix return type of cups.py
* Usb idVendor/idProduct are integers
* self.default_args is always defined
* tweak usb_args, PEP589 is better
* lp.py: reassure mypy
* correctly cast call to CashDrawerError()
* update CUPS test
* add missing close() method in metaclass
* document a bug in typeshed
* query_status() returns bytes as seen in constants.py
* remove more SIX usage
* test examples too
* remove type comment where type is annotated
* adapt behavior of cups printer to match other implementations

---------

Co-authored-by: Patrick Kanzler <dev@pkanzler.de>
Co-authored-by: Patrick Kanzler <4189642+patkan@users.noreply.github.com>

test/test_function_cut.py

@@ -1,5 +1,3 @@
-import six
-
 import escpos.printer as printer
 from escpos.constants import GS
 
@@ -8,5 +6,5 @@ def test_cut_without_feed():
     """Test cut without feeding paper"""
     instance = printer.Dummy()
     instance.cut(feed=False)
-    expected = GS + b"V" + six.int2byte(66) + b"\x00"
+    expected = GS + b"V" + bytes((66,)) + b"\x00"
     assert instance.output == expected