docs: update README to reflect the demo details

Signed-off-by: Graham White <[email protected]>

README.md

@@ -1,5 +1,5 @@
 ---
-title: Granite 3.0 Chat template example.
+title: Granite 3.1 8b Instruct
 emoji: 📝
 colorFrom: blue
 colorTo: indigo
@@ -8,5 +8,5 @@ sdk_version: 5.9.1
 app_file: src/app.py
 pinned: false
 license: apache-2.0
-short_description: Chat with IBM Granite 3.0
+short_description: Chat with IBM Granite 3.1 8b Instruct
 ---