support vectorized percentile input in roll_quantile

[ethanbsmith]

great package. TY for all your work

would you consider supporting calculating multiple quantiles in a single pass in roll_quantile like stats::quantile does
something like : roll::roll_quantile(1:100, width=10, p=c(.16, .5, .84))

[jasonjfoster]

Thanks for the feedback. I currently don't have plans to support it but we can see whether there's demand or collaborators that want to help.