changed license identifier from GPLv3 to GPL-3.0 so that it is a "valid SPDX license expression", see https://github.com/phetsims/tasks/issues/394
changed license identifier from GPLv3 to GPL-3.0 so that it is a "valid SPDX license expression", see https://github.com/phetsims/tasks/issues/394

phetsims/fraction-matcher,phetsims/fraction-matcher,phetsims/fraction-matcher