little mistake in the repo example: change logs_root to logs_dir

[mjmaher987]

there is no argument with name logs_root. but when you change it to logs_dir it's ok. example:
! python3 FedEM/run_experiment.py cifar10 FedAvg
--n_learners 1
--n_rounds 200
--bz 128
--lr 0.01
--lr_scheduler multi_step
--log_freq 5
--device cuda
--optimizer sgd
--seed 1234
--logs_dir /content
--verbose 1