Add pipeline tag and library name

This PR enhances the model card by adding the `pipeline_tag` and `library_name` to the metadata.

- The `pipeline_tag: image-to-image` ensures the model is discoverable through the Hugging Face Hub's pipeline filters for image generation and manipulation tasks.
- The `library_name: diffusers` enables the automated "how to use" code snippet for the `diffusers` library, making it easier for users to get started with the model.

Please review and merge if these additions are accurate.

README.md

@@ -1,5 +1,7 @@
 ---
 license: mit
+pipeline_tag: image-to-image
+library_name: diffusers
 ---
 
 # Implementation of FLUX-Text