tox: Update Mako to 1.0.4

[test] [feature] The default test runner is now py.test. Running “python
setup.py test” will make use of py.test instead of nose. nose still works as a
test runner as well, however.

[lexer] [bug] Major improvements to lexing of intricate Python sections which
may contain complex backslash sequences, as well as support for the bitwise
operator (e.g. pipe symbol) inside of expression sections distinct from the
Mako “filter” operator, provided the operator is enclosed within parentheses or
brackets. Pull request courtesy Daniel Martin.

[feature] Added new method Template.list_defs(). Pull request courtesy Jonathan
Vanasco.

tox.ini

@@ -22,7 +22,7 @@ deps =
     httpbin==0.4.1
     hypothesis==3.1.0
     itsdangerous==0.24
-    Mako==1.0.3
+    Mako==1.0.4
     parse==1.6.6
     parse-type==0.3.4
     py==1.4.31