Add 'transformers' tag

## Add tag: transformers

This PR adds the `transformers` tag to the model repository.

**Changes:**
- Added `transformers` to model tags
- Updated from 2 to 3 tags

**Current tags:** license:apache-2.0, region:us
**New tags:** license:apache-2.0, region:us, transformers

README.md

@@ -1,3 +1,7 @@
 ---
 license: apache-2.0
+tags:
+- license:apache-2.0
+- region:us
+- transformers
 ---