setup.cfg: add missing Python version trove classifiers

Signed-off-by: Filipe Laíns <lains@riseup.net>

Author: FFY00

setup.cfg

@@ -12,6 +12,8 @@ classifiers =
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
     Topic :: System :: Operating System Kernels :: Linux
 url = https://github.com/FFY00/python-ioctl