requirements: Add comment explaining why CommonMark can't be upgraded.

Fixes zulip#3398.
skapil · Jan 24, 2017 · 1d1dcab · 1d1dcab
1 parent 4e78ca3
commit 1d1dcab
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/requirements/docs.txt b/requirements/docs.txt
@@ -12,6 +12,9 @@ recommonmark==0.4.0
 # Dependencies of Sphinx
 alabaster==0.7.9
 babel==2.3.4
+# Upgrading to the latest version of CommonMark breaks the
+# compatibility with recommonmark.  See
+# https://github.com/rtfd/recommonmark/issues/24
 CommonMark==0.5.4
 docutils==0.13.1
 imagesize==0.7.1