This commit refactors the way git commands are executed across the `changelog_generator` and `commit_generator` modules, leveraging a shared utility function and enhancing error handling.
* **Enhancements & Refinements**
* Replaced the internal `_exec_git` method in both `ChangelogGenerator` and `CommitEngine` with the common `run_git_command` utility from `devgen.utils`.
* Standardized and improved error handling for git command failures by wrapping `run_git_command` calls in `try-except subprocess.CalledProcessError` blocks, providing more precise logging and raising `CommitEngineError` where applicable.
* Adjusted error handling for `git reset HEAD` operations to gracefully ignore potential failures, ensuring smoother execution for non-critical resets.
* Refined the `is_ahead_of_remote` check in `CommitEngine` to correctly handle scenarios with no upstream configured by using `check=False` for `run_git_command` and broadening error catch.
sankalp