Change pipeline tag

Hey, I changed the tag to `video-text-to-text` for easier discoverability of the model

README.md

@@ -3,7 +3,7 @@ license: apache-2.0
 language:
 - en
 - zh
-pipeline_tag: visual-question-answering
+pipeline_tag: video-text-to-text
 ---
 # Kangaroo: A Powerful Video-Language Model Supporting Long-context Video Input
 
@@ -77,4 +77,4 @@ If you find it useful for your research , please cite related papers/blogs using
 	author={Jiajun Liu and Yibing Wang and Hanghang Ma and Xiaoping Wu and Xiaoqi Ma and Jie Hu},
 	month={July},
 	year={2024}
-}
+}