Export property values to a dictionary with environment variable names as keys.

def to_envvars(self):
        """
        Export property values to a dictionary with environment variable names as keys.
        """
        export = {}
        for prop_name in self.profile_properties:
            prop = self._get_prop(prop_name)
            value = self[prop_name]
            if value is not None:
                export[prop.get_envvar(self)] = prop.to_str(self, value)
        if self._profile_parent_name:
            export[
                f"{self._envvar_prefix}PARENT_PROFILE".upper()
            ] = self._profile_parent_name
        return export