AMLII-2172 - remove black from tox (#873)

tox.ini

@@ -6,7 +6,7 @@ envlist =
     flake8
     integration
     mypy
-    black
+    # black - see comments below
 
 [testenv]
 passenv = DD_TEST_CLIENT*
@@ -43,15 +43,18 @@ deps =
     flake8==3.7.9
 commands = flake8 datadog
 
-[testenv:black]
-deps =
-    black
-commands = black --line-length 120 {posargs} datadog
+# Black isn't safe to run while support is being maintained for python2.7, but 
+# can be re-enabled when support for 2.7 is dropped. 
+#
+# [testenv:black]
+# deps =
+#     black
+# commands = black --line-length 120 {posargs} datadog
 
 [testenv:mypy]
-# Mypy requires Python 3.5 or higher (but it can still type-check Python 2
+# Mypy requires Python >= 3.5 and <=3.8  (but it can still type-check Python 2
 # code).
-basepython = python3
+basepython = python3.8
 skip_install = true
 deps =
     mypy==0.770