v8.0.11: Improved GPU training time

✨ New features and improvements

• Speed up GPU training time with up to ~25% by using cuBLAS for computing Frobenius norms in gradient clipping.
• Give preference to AppleOps (if available) when calling get_ops("cpu").
• Support missing values in CategoricalCrossEntropy when the labels are integers.
• Provide the option to run model.walk with depth-first traversal.
• Wrap forward/init callbacks of a Model in with_debug and with_nvtx_range to facilitate recursively instrumenting models.

🔴 Bug fixes

• Fix issue #537: Fix replace_node on nodes with indirect node refs.

👥 Contributors

@adrianeboyd, @danieldk, @honnibal, @ines, @svlandeg