Fix redirect: finetuning_torchvision_models → transfer_learning_tutorial (#3721)

Fixes #3720
   
## Description
The original tutorial covered Image Classification with
hymenoptera_data.
Changed redirect from torchvision_tutorial (Object Detection) to 
transfer_learning_tutorial (same task and dataset).

Author: sjp611

beginner_source/finetuning_torchvision_models_tutorial.rst

@@ -1,10 +1,10 @@
 Finetuning Torchvision Models
 =============================
 
-This tutorial has been moved to https://pytorch.org/tutorials/intermediate/torchvision_tutorial.html
+This tutorial has been moved to https://pytorch.org/tutorials/beginner/transfer_learning_tutorial.html
 
 It will redirect in 3 seconds.
 
 .. raw:: html
 
-   <meta http-equiv="Refresh" content="3; url='https://pytorch.org/tutorials/intermediate/torchvision_tutorial.html'" />
+   <meta http-equiv="Refresh" content="3; url='https://pytorch.org/tutorials/beginner/transfer_learning_tutorial.html'" />