Update requirements.txt for text_to_image (#7892)

Update requirements.txt

If the datasets library is old, it will not read the metadata.jsonl and the label will default to an integer of type int.
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>

examples/text_to_image/requirements.txt

 accelerate>=0.16.0
 torchvision
 transformers>=4.25.1
-datasets
+datasets>=2.19.1
 ftfy
 tensorboard
 Jinja2