docs: upgrade Sphinx to 2.1.2, require Python 3 to build docs.

dw · dw · commit a91a8bf19c20 · 2019-08-10T17:20:30.000+01:00
diff --git a/docs/requirements.txt b/docs/requirements.txt
@@ -1,3 +1,3 @@
-Sphinx==1.7.1
-sphinxcontrib-programoutput==0.11
+Sphinx==2.1.2
+sphinxcontrib-programoutput==0.14
 alabaster==0.7.10
