* Remove f-string, since it's not supported by Python 3.5 (#5330) * Remove f-string, since it's not supported by Python 3.5 * Add Python 3.5 to CI, to ensure compatibility * Remove duplicated matplotlib * Show deprecation notice for Python 3.5 * Fix lint * Fix lint * Fix a unit test that mistook MINOR ver for PATCH ver * Enforce only major version in JSON model schema * Bump version to 1.1.0-SNAPSHOT