Pin recommonmark version for documentation

For linebreaks in >= 0.6.0 (https://github.com/readthedocs/recommonmark/pull/162)

diff --git a/docs/requirements.txt b/docs/requirements.txt
new file mode 100644 (file)
index 0000000..a44c04c
--- /dev/null
+++ b/docs/requirements.txt
@@ -0,0 +1 @@
+recommonmark==0.7.1