Merge branch '3.1.x'

diff --cc tox.ini
index 064ca2e4af2fe1477675ffecca32503e4e06297d,5e15000d05a71a848901a5eeea43b695c0572031..da81aa65c645e329cc8335c58c4a0e0eb9581007
--- 1/tox.ini
--- 2/tox.ini
+++ b/tox.ini
@@@ -15,9 -15,9 +15,6 @@@ use_frozen_constraints = tru
  deps = -r requirements/tests.txt
  commands = pytest -v --tb=short --basetemp={envtmpdir} {posargs}
  
--[testenv:py37,py3.7]
--deps = -r requirements/tests37.txt
--
  [testenv:style]
  deps = pre-commit
  skip_install = true