Set `library_name` to `tf-keras`.

Model 'keras-dreambooth/dreambooth_diffusion_clay_cups' 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This PR updates the model card to replace the explicit `library_name: keras` metadata which is now outdated by `library_name: tf-keras`.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

@@ -1,13 +1,12 @@
 ---
-library_name: keras
+library_name: tf-keras
 tags:
-  - keras
-  - diffusers
-  - stable-diffusion
-  - text-to-image
-  - keras-dreambooth
+- diffusers
+- stable-diffusion
+- text-to-image
+- keras-dreambooth
 widget:
-  - text: a photo of traditional cups image in bng clay style 
+- text: a photo of traditional cups image in bng clay style
 ---
 
 ## Model description