Fix: Updated densenetXXX URLs to valid links

[a-sato-vs]

What does this PR do?

This PR fixes the issue with downloading pretrained weights for densenetXXX models. The URLs in pretrainedmodels/models/torchvision_models.py were outdated or invalid, causing SSL errors during download.

Changes made:

• Updated the model_urls dictionary with valid URLs for densenetXXX models.

Related Issue:

Fixes #230

Testing:

• Successfully downloaded and loaded densenet201 weights after the fix.
• No issues observed during testing.

Let me know if there are further changes or testing required. Thanks for reviewing!