Bumping tox version.

Author: igorborgest

requirements-dev.txt

@@ -6,7 +6,7 @@ mypy~=0.780
 isort~=4.3.21
 pydocstyle~=5.0.2
 doc8~=0.8.1
-tox~=3.15.1
+tox~=3.15.2
 pytest~=5.4.3
 pytest-cov~=2.9.0
 pytest-xdist~=1.32.0