Add text-generation pipeline tag

Adds the `text-generation` pipeline tag to the model, so it's easier to find on the Hub.

README.md

@@ -10,6 +10,7 @@ language:
 - th
 datasets:
 - scb10x/typhoon-t1-3b-research-preview-data
+pipeline_tag: text-generation
 ---
 
 # Typhoon T1 3B (Research Preview)