adjust anyhow scope and remove unused dependencies

[neithanmo]

This PR introduces some adjustments to the Cargo.toml configuration to better align with the crate's compatibility and usage requirements, particularly focusing on the removal of the tracing dependency and the relocation of anyhow to dev-dependencies. These changes are motivated by the need to ensure compatibility with the thumbv6m-none-eabi target, which does not support atomic operations required by tracing and std/alloc.

• Removed tracing and tracing-subscriber Dependencies: Due to incompatibility with the thumbv6m-none-eabi target, which lacks support for atomic operations, the tracing and tracing-subscriber dependencies have been removed. Besides that, the tracing dependencies are not used within the crate.

• Relocated anyhow to Dev-Dependencies: The anyhow crate is now moved to dev-dependencies, reflecting its usage strictly in development contexts and tests.

• Minor Adjustments and Cleanup: The PR also includes minor adjustments for consistency and clarity in the Cargo.toml file, such as formatting and the explicit inclusion of hashbrown under the arkworks feature flag(can be also put behind the std or alloc features).

With these changes, we can compile this crate for the thumbv6m-non-eabi target, by enabling the u32_backend and disabling std and alloc features.

[redshiftzero]

LGTM