Move doc requirements to doc
and update tox to later version
Change-Id: I4c07e622f2285513c86f168c15b375e62b5594ad
diff --git a/doc/requirements.txt b/doc/requirements.txt
new file mode 100644
index 0000000..856012d
--- /dev/null
+++ b/doc/requirements.txt
@@ -0,0 +1,9 @@
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
+
+sphinx>=2.0.0,!=2.1.0 # BSD
+openstackdocstheme>=2.2.1 # Apache-2.0
+# releasenotes
+reno>=3.1.0 # Apache-2.0
+