Use python standard library mock

Author: Anthchirp

requirements_dev.txt

@@ -1,7 +1,6 @@
 bump2version==1.0.0
 coverage==5.3
 flake8==3.8.3
-mock==3.0.5
 pip==20.2.3
 pytest==6.1.0
 Sphinx==3.2.1

setup.py

@@ -13,7 +13,7 @@
 
 setup_requirements = []
 
-test_requirements = ["mock", "pytest"]
+test_requirements = ["pytest"]
 
 setup(
     author="Markus Gerstel",

tests/test_procrunner.py

@@ -1,5 +1,5 @@
 import copy
-import mock
+from unittest import mock
 import os
 import pathlib
 import procrunner