Checks whether the lock file is still up to date with the current hash.

def is_fresh(self):  # type: () -> bool
        """
        Checks whether the lock file is still up to date with the current hash.
        """
        lock = self._lock.read()
        metadata = lock.get("metadata", {})

        if "content-hash" in metadata:
            return self._content_hash == lock["metadata"]["content-hash"]

        return False