- Added missing dependency to setup.py file. So pypi can install the dependency.

Author: rvelaVenafi

setup.py

@@ -17,7 +17,7 @@
       packages=['vcert', 'vcert.parser', 'vcert.policy'],
       install_requires=['requests<=2.25.1', 'python-dateutil<=2.8.1', 'certvalidator<=0.11.1', 'six<=1.15.0',
                         'enum34;python_version<"3.4"', 'ipaddress;python_version<"3.3"',
-                        'cryptography<=3.3.2', 'future;python_version<"3"', 'ruamel.yaml<0.17'],
+                        'cryptography<=3.3.2', 'future;python_version<"3"', 'ruamel.yaml<0.17', 'pynacl>=1.4.0'],
       description='Python client library for Venafi Trust Protection Platform and Venafi Cloud.',
       long_description=long_description,
       long_description_content_type="text/markdown",