Return a dict based on `key=value` pair strings.

def _parse_service_env_vars(self, env_vars):
        """Return a dict based on `key=value` pair strings.
        """
        env = {}
        for var in env_vars:
            # Yeah yeah.. it's less performant.. splitting twice.. who cares.
            k, v = var.split('=')
            env.update({k: v})
        return env