Add `transformers` as library_name

This update will explicitly tag this model as a `transformers` model, which will automatically add code snippets and deploy buttons on the model page. It will also help referencing the model on the platform.

README.md

@@ -7,10 +7,11 @@ base_model:
 - Qwen/Qwen2-72B
 pipeline_tag: image-text-to-text
 tags:
-  - multimodal
-  - olmo
-  - molmo
-  - pixmo
+- multimodal
+- olmo
+- molmo
+- pixmo
+library_name: transformers
 ---
 
 <img src="molmo_logo.png" alt="Logo for the Molmo Project" style="width: auto; height: 50px;">