Update getting started guide to use PyTorch ResNet50 (#2750)
* Update getting started guide to use PyTorch ResNet50
Replace TensorFlow-based ResNet50 example with PyTorch/torchvision, which
works on Apple Silicon (M1/M2) Macs. Also updates getting-started-own-model.md
for consistency.
Changes:
- Switch from tensorflow to torch/torchvision (auto-downloads weights)
- Remove manual weight download step
- Use python_requirements instead of deprecated python_packages
- Update Python version from 3.11 to 3.12
- Remove cog debug and --separate-weights sections
- Add GPU tip for users with NVIDIA GPUs
Closes #336
Supersedes #1880
* Use python_requirements in README, remove inline requirements.txt snippet
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Co-authored-by: Morgan Fainberg <code@tempusfrang.it>
