Fix typo.

Author: paulross

requirements.txt

@@ -0,0 +1,24 @@
+alabaster==0.7.12
+Babel==2.8.0
+certifi==2020.6.20
+chardet==3.0.4
+docutils==0.16
+idna==2.10
+imagesize==1.2.0
+Jinja2==2.11.2
+MarkupSafe==1.1.1
+packaging==20.4
+Pygments==2.7.1
+pyparsing==2.4.7
+pytz==2020.1
+requests==2.24.0
+six==1.15.0
+snowballstemmer==2.0.0
+Sphinx==3.2.1
+sphinxcontrib-applehelp==1.0.2
+sphinxcontrib-devhelp==1.0.2
+sphinxcontrib-htmlhelp==1.0.3
+sphinxcontrib-jsmath==1.0.1
+sphinxcontrib-qthelp==1.0.3
+sphinxcontrib-serializinghtml==1.1.4
+urllib3==1.25.11