Update pipeline tag

This PR fixes the pipeline tag for the model, making sure it can be found at https://huggingface.co/models?pipeline_tag=image-text-to-text.

README.md

@@ -1,7 +1,7 @@
 ---
 inference: false
 license: apache-2.0
-
+pipeline_tag: image-text-to-text
 ---
 
 # Model Card