readme : add 3rd party collama reference to UI list (ggml-org#4840)

Add a VSCode extension for llama.cpp reference to UI list

Author: iohub

README.md

@@ -137,6 +137,7 @@ as the main playground for developing new features for the [ggml](https://github
 - [semperai/amica](https://github.com/semperai/amica)
 - [psugihara/FreeChat](https://github.com/psugihara/FreeChat)
 - [ptsochantaris/emeltal](https://github.com/ptsochantaris/emeltal)
+- [iohub/collama](https://github.com/iohub/coLLaMA)
 
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