chore(project): update documentation dependencies

This resolves some security warnings with urllib3 https://nvd.nist.gov/vuln/detail/CVE-2019-11324

Author: kylef

docs/Pipfile.lock

@@ -1,23 +1,23 @@
 -i https://pypi.org/simple
 alabaster==0.7.12
 babel==2.6.0
-certifi==2018.11.29
+certifi==2019.3.9
 chardet==3.0.4
 docutils==0.14
 idna==2.8
 imagesize==1.1.0
-jinja2==2.10
-markupsafe==1.1.0
+jinja2==2.10.1
+markupsafe==1.1.1
 packaging==19.0
 parsimonious==0.7.0
 pygments==2.3.1
-pyparsing==2.3.1
-pytz==2018.9
+pyparsing==2.4.0
+pytz==2019.1
 requests==2.21.0
 six==1.12.0
 snowballstemmer==1.2.1
 sphinx-js==2.7.1
-sphinx-rtd-theme==0.4.2
-sphinx==1.8.3
+sphinx-rtd-theme==0.4.3
+sphinx==1.8.5
 sphinxcontrib-websupport==1.1.0
-urllib3==1.24.1
+urllib3==1.24.2