CRASH on cargo provider

[vemilano]

Description

Hello,

In cargo_provider.py on line 86, there is version_workspace = package_content["version"]["workspace"].
This causes commitizen to crash (traceback) under the following conditions:

• you have a cargo workspace
• you have a crate that is a worskpace member
• this crate has (in [package] key) a version = 0.1.0

The error is: TypeError: string indices must be integers, not 'str'

This could be fixed by checking that workspace key exists (and check that it is True, which is already done)

Steps to reproduce

• you have a cargo workspace
• you have a crate that is a worskpace member
• this crate has (in [package] key) a version = 0.1.0

Current behavior

TypeError: string indices must be integers, not 'str'

Desired behavior

no crash

Screenshots

No response

Environment

Commitizen Version: 4.16.2