Link to developer docs from python-tuf blog

Signed-off-by: Joshua Lock <[email protected]>

Author: joshuagl

docs/index.md

@@ -2,4 +2,5 @@
 title: "Python-TUF development blog"
 ---
 This is the development blog for the [Python-TUF](https://github.com/theupdateframework/python-tuf) project, welcome!
+If you want to learn how to use Python-TUF, check out our [developer documentation](https://theupdateframework.readthedocs.io/en/latest/).