A staffing agency cast the net too wide in its bid to prevent a former executive from doing any work for his new employer, a federal judge has held.In a written opinion Tuesday, U.S. District Judge Sara L. Ellis ruled the covenant not to compete that Medix Staffing Solutions Inc. required Daniel Dumrauf to sign is unenforceable because it is too broad.The covenant stated Dumrauf could not “own, manage, operate, control, be employed by, participate in or be connected in any manner” with a company that competes …