rowMeans() does can be used one its own without dplyr::mutate()
within a pipe.
mutate_rowmeans(data, new_var, ..., na.rm = FALSE)
the dataframe that contains the variables to get the row means from
the name of the new variable for which you'll put the row means in quotes
the variables (unquoted) to be included in the row means
should the missing values be ignored? default is FALSE
the row means included within the data.frame