Update Caltech Birds URL to point to the dataset's official website.

PiperOrigin-RevId: 660371746

Author: fineguy

tensorflow_datasets/image_classification/caltech_birds.py

@@ -33,7 +33,7 @@
 Annotations include bounding boxes, segmentation labels.
 """
 
-_URL = "http://www.vision.caltech.edu/visipedia/CUB-200.html"
+_URL = "https://www.vision.caltech.edu/datasets/cub_200_2011/"
 _CITATION = """\
 @techreport{WelinderEtal2010,
 Author = {P. Welinder and S. Branson and T. Mita and C. Wah and F. Schroff and S. Belongie and P. Perona},