Add pipeline tag

This PR ensures the model can be found at https://huggingface.co/models?pipeline_tag=video-text-to-text&sort=trending

README.md

@@ -1,4 +1,5 @@
 ---
+pipeline_tag: video-text-to-text
 license: apache-2.0
 base_model:
 - Qwen/Qwen2.5-7B-Instruct