Pin jmespatch dependency version
Can this library pin its jmespath dependency to a specific version?  Currently, it depends on the development branch of the jmespath GitHub repo - which is not stable nor deterministic.

Currently, this project's setup.py requires version 0.7.1 but the upstream GitHub repo/branch does not deliver that version - so this project's dependency graph is disconnected.

This can result in runtime errors for downstream consumers - like my organization did today.

diff --git a/setup.py b/setup.py
index ea3260e99..b1ed6c109 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@ import sys
 from setuptools import setup, find_packages
 
 
-requires = ['jmespath==0.7.1',
+requires = ['jmespath>=0.7.1,<1.0.0',
             'python-dateutil>=2.1,<3.0.0',
             'docutils>=0.10']
 
['setup.py']