Bumping codecov version

requirements.testing.txt

@@ -1,7 +1,7 @@
 pytest>=5.4.3,<6.2.5
 pytest-cov>=2.10.0,<3.0.0
 pytest-runner>=5.2,<5.3.1
-codecov>=2.1.7,<2.1.12
+codecov==2.1.13
 responses>=0.10.15,<0.14.0
 six>=1.15.0,<1.16.0
 tox>=3.15.2,<3.24.4