doc: update link to current install webpage (#1020)

Author: asoplata

README.md

@@ -120,5 +120,4 @@ JOSS](https://doi.org/10.21105/joss.05848):
 [Contributing Guide]: https://jonescompneurolab.github.io/hnn-core/stable/contributing.html
 
 <!-- TODO: Once we have a "stable" version of the install webpage, need to update this link to it: -->
-<!-- TODO: Once the install page is merged into "dev", we need to update this link to it: -->
-[Installation Guide]: https://github.com/asoplata/hnn-core/blob/iss969-authoring/doc/install.md
+[Installation Guide]: https://jonescompneurolab.github.io/hnn-core/dev/install.html