Function homebins::installed_manifest_version

pub fn installed_manifest_version(
    dirs: &InstallDirs, 
    manifest: &Manifest
) -> Result<Option<Versioning>, Error>

Get the installed version of the given manifest.

Attempt to invoke the version check denoted in the manifest, i.e. the given binary with the version check arguments, and use the pattern to extract a version number.

Return None if the binary doesn't exist or its output doesn't match the pattern; fail if we cannot invoke it for other reasons or if we fail to parse the version from other.