ci(deps): Update dependency pytest-mock to v3

Author: renovate[bot]

setup.py

@@ -58,7 +58,7 @@ def read(fname: str) -> str:
         "PyHamcrest==1.10.1",
         "pytest-cov",
         "pytest-flask",
-        "pytest-mock==1.13.0",
+        "pytest-mock==3.8.1",
         "pytest-runner",
     ],
     extras_require={