Update urllib3 and Jinja2 dependencies to latest versions

This addresses security vulnerabilities:

* urllib3: CVE-2019-11324
* jinja2: CVE-2019-10906

requirements.txt

@@ -2,7 +2,7 @@
 # This file is autogenerated by pip-compile
 # To update, run:
 #
-#    pip-compile --output-file requirements.txt requirements.in
+#    pip-compile --upgrade-package urllib3 requirements.in
 #
 aafigure==0.6
 alabaster==0.7.12         # via sphinx
@@ -16,7 +16,7 @@ docutils==0.14
 html5lib==1.0.1           # via xhtml2pdf
 idna==2.8                 # via requests
 imagesize==1.1.0          # via sphinx
-jinja2==2.10              # via sphinx
+jinja2==2.10.1            # via sphinx
 kiwisolver==1.0.1         # via matplotlib
 lxml==4.3.1               # via svglib
 markupsafe==1.1.0         # via jinja2
@@ -41,6 +41,6 @@ subprocess32==3.5.3       # via matplotlib
 svglib==0.9.0
 tinycss2==0.6.1           # via cssselect2, svglib
 typing==3.6.6             # via sphinx
-urllib3==1.24.1           # via requests
+urllib3==1.24.3
 webencodings==0.5.1       # via html5lib, tinycss2
 xhtml2pdf==0.2.3