non-free.md: fix section title/case

non-free.md

@@ -55,7 +55,7 @@
 - [untrusted](https://github.com/AlexNisnevich/untrusted) - Unique puzzle game designed for geeks and developers, where you solve the puzzles in the game by reading and writing Javascript. ([Demo](http://alex.nisnevich.com/untrusted/)) `CC-BY-NC-SA-3.0` `Nodejs`
 
 
-### Internet Of Things (IoT)
+### Internet of Things (IoT)
 
 - [Atman IoT](https://atman-iot.com) - Self hosted IoT gateway focused on IoT solution rapid prototyping, packaged as stand alone docker container, promising to help you build your IoT solution in a week. ([Demo](https://atman-iot.com/signup-redirect)) `⊘ Proprietary` `Nodejs`