Function tag_date 

pub fn tag_date(
    repo_path: &Path,
    tag_name: &str,
) -> Result<DateTime<Utc>, Error>

Resolves the author/tagger timestamp for tag_name.

For annotated tags, returns the tagger date. For lightweight tags (which point directly to a commit), returns the committer date.

Errors

Returns Error::OpenRepo if the repository cannot be opened, Error::TagNotFound if the tag does not exist, or Error::Object if the timestamp cannot be decoded.