Your package gazebo failed to build from source in current F28. https://koji.fedoraproject.org/koji/taskinfo?taskID=25252754 For details on mass rebuild see https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild
A build was successfull: gazebo-8.3.0-1.fc28 [1]. An update was found in bodhi [2]. [1] https://koji.fedoraproject.org/koji/buildinfo?buildID=1054091 [2] https://bodhi.fedoraproject.org/updates/?search=gazebo-8.3.0-1.fc28