bug with superscript

[ConYel]

Hello and thank you for this package!
It seems that when we put superscript on the "package" it doesn't seem to print it.

library(hexSticker)
s <- sticker(~plot(cars, cex=.5, cex.axis=.5, mgp=c(0,.3,0), xlab="", ylab=""),
          package=paste0("hexSticke",supsc('r')), p_size=20, s_x=.8, s_y=.6, s_width=1.4, s_height=1.2,
          filename="inst/figures/baseplot.png")
## it does work with numbers but not with letters

s <- sticker(~plot(cars, cex=.5, cex.axis=.5, mgp=c(0,.3,0), xlab="", ylab=""),
          package=paste0("hexSticker", supsc('0'))p_size=20, s_x=.8, s_y=.6, s_width=1.4, s_height=1.2,
          filename="inst/figures/baseplot.png")