Add link to Nightly CI badge

Author: jobselko

README.md

@@ -1,7 +1,7 @@
 # pulp_python
 
 [![PyPI](https://img.shields.io/pypi/v/pulp_python)](https://pypi.python.org/pypi/pulp_python)
-![Pulp Nightly CI/CD](https://github.com/pulp/pulp_python/actions/workflows/nightly.yml/badge.svg)
+[![Pulp Nightly CI/CD](https://github.com/pulp/pulp_python/actions/workflows/nightly.yml/badge.svg)](https://github.com/pulp/pulp_python/actions/workflows/nightly.yml)
 
 A Pulp plugin to support hosting your own pip compatible Python packages.