Open
Description
Describe the feature
This issue requests to support to add information of git hash in version file during MMCV installation.
Motivation
The current collect_env() or version file does not provide a way to store the information of git hash of MMCV or mm repos.
It is inconvenient when debug or benchmarking on a specific branch and the developers need to manually check the MMCV version.
The information is also helpful to reproduce the experiments or bugs when necessary.
Additional context
A naive way is to add the git hash information during installation, e.g., write it in a file and provide an API to read it. Any implementation strategy is acceptable as long as it is elegant.