Update iso8601 from 0.1.11 to 0.1.12

Author: pyup-bot

{{cookiecutter.project_slug}}/requirements.txt

@@ -9,7 +9,7 @@ enum34==1.1.6
 funcsigs==1.0.2
 glob2==0.5
 imagesize==0.7.1
-iso8601==0.1.11
+iso8601==0.1.12
 Jinja2==2.9.6
 Mako==1.0.7
 MarkupSafe==1.0