Run flask tests with 3.7 and 3.8

Author: leplatrem

tox.ini

@@ -8,7 +8,7 @@ envlist =
     # https://docs.djangoproject.com/en/2.0/faq/install/#what-python-version-can-i-use-with-django
     py{27,36}-dj111-tests,
     py{36,37,38}-dj{21,22}-tests,
-    py{27,36}-fl{011,012,10}-tests,
+    py{27,36,37,38}-fl{011,012,10}-tests,
     py{36,37,38}-s19-tests,
 
 [testenv]