cx_rl: remove deprecated tests_require

Author: TarikViehmann

extensions/reinforment_learning/cx_rl_multi_robot_mppo/setup.cfg

@@ -2,3 +2,5 @@
 script_dir=$base/lib/cx_rl_multi_robot_mppo
 [install]
 install_scripts=$base/lib/cx_rl_multi_robot_mppo
+[options.extras_require]
+test = pytest

extensions/reinforment_learning/cx_rl_multi_robot_mppo/setup.py

@@ -31,7 +31,6 @@
     maintainer_email='viehmann@kbsg.rwth-aachen.de',
     description='Multi-robot maskable proximal policy optimization (mppo) implementation',
     license='Apache-2.0',
-    tests_require=['pytest'],
     entry_points={
         'console_scripts': ['cx_rl_node = cx_rl_multi_robot_mppo.cx_rl_node:main'],
     },