cmd2: Constrain version to >= 1.3.0 but < 2.0.0

2.0.0 introduces several incompatible changes, see
https://github.com/python-cmd2/cmd2/blob/master/CHANGELOG.md
as well as https://github.com/python-cmd2/cmd2/issues/1120

As we want to be able to use what distributions ship, let's stay
with 1.x for now.  If piip is used, use 1.5

Change-Id: Iecc953269d5ae9ed9f31b829743c63bdfd29fa61
diff --git a/contrib/jenkins.sh b/contrib/jenkins.sh
index 27f0245..91dcdd2 100755
--- a/contrib/jenkins.sh
+++ b/contrib/jenkins.sh
@@ -19,7 +19,7 @@
 . venv/bin/activate
 pip install pytlv
 pip install pyyaml
-pip install cmd2
+pip install cmd2==1.5
 pip install jsonpath-ng
 pip install construct
 pip install bidict