bandit_sim.R renderTable align argument fix
bandit_sim.R renderTable align argument fix

fixed error's message:
Warning: Error in origRenderFunc: `align` must contain only the characters `l`, `c`, `r` and/or `?` andhave length either equal to 1 or to the total number of columns
Stack trace (innermost first):
    79: origRenderFunc
    78: output$tab
     3: <Anonymous>
     2: do.call
     1: rmarkdown::run

related to https://www.coursera.org/learn/bayesian/discussions/weeks/1/threads/mTrbMHd8EeaX3g4cIbI3IQ
StatsWithR/statsr