Set `library_name` to `tf-keras`.

Model 'keras-dreambooth/dreambooth-seymour-cat' seems to be compatible only with "Keras 2" and not "Keras 3". To distinguish them, models compatible with legacy Keras 2.x should be tagged as `tf-keras` while models compatible with Keras 3.x are tagged as `keras`.

This PR updates the model card to replace the explicit `library_name: keras` metadata which is now outdated by `library_name: tf-keras`. Updating this metadata will facilitate its discoverability and usage.

For more information about `keras` and `tf-keras` library names, check out this pull request: https://github.com/huggingface/huggingface.js/pull/774.

README.md

@@ -1,15 +1,15 @@
 ---
+library_name: tf-keras
+pipeline_tag: text-to-image
+tags:
+- keras-dreambooth
+- nature
+- cat
 title: Dreambooth Seymour Cat Model
 emoji: 🐱
 colorFrom: orange
 colorTo: brown
-tags:
-  - keras-dreambooth
-  - nature
-  - cat
 pinned: false
-library_name: keras
-pipeline_tag: text-to-image
 ---
 
 ## Model description