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/setup.py b/setup.py
index 2ef498f..e8e4173 100644
--- a/setup.py
+++ b/setup.py
@@ -12,7 +12,7 @@
         "pyscard",
         "serial",
         "pytlv",
-        "cmd2 >= 1.3.0",
+        "cmd2 >= 1.3.0, < 2.0.0",
         "jsonpath-ng",
         "construct >= 2.9",
         "bidict",