v0.11.40

Removed

• #v1 Remove numpy and pytorch layouts, as these are insecure and not worth the
  effort in maintaining. Safetensors is instead the recommended conversion case.
• #v1 Remove LeafHandler as a user-exposed layer (it remains as an internal layer).

Added

• #v1 Allow a context to be default-configured for all Checkpointer
  operations.

Changed

• Upgrade to TensorStore>=0.1.84 (and Python>=3.11 as a consequence.)