fix issue 2628

Author: SubhamJM

.github/CONTRIBUTING.md

@@ -1,4 +1,4 @@
 Contributing
 ============
 
-We welcome your contributions! Please see the [contributing](http://pvlib-python.readthedocs.io/en/latest/contributing.html) page for information about how to contribute.
+We welcome your contributions! Please see the [contributing](https://pvlib-python.readthedocs.io/en/stable/contributing/index.html) page for information about how to contribute.