Security updates to requirements

Author: Bjwebb

requirements.txt

@@ -19,12 +19,12 @@ docutils==0.13.1
 future==0.16.0
 idna==2.5
 imagesize==0.7.1
-Jinja2==2.9.6
+Jinja2==2.10.3
 MarkupSafe==1.0
 Pygments==2.2.0
 pytz==2017.2
-requests==2.18.1
+requests==2.22.0
 six==1.10.0
 snowballstemmer==1.2.1
 sphinxcontrib-websupport==1.0.1
-urllib3==1.22
+urllib3==1.25.7