avoid use of dev leaflet version

By not needing the pane option in the rasters, the specific version of leaflet (rstudio/leaflet#692) isn't required.

Author: RWParsons

server.R

@@ -171,7 +171,6 @@ function(input, output, session) {
           data=new_layer,
           x=raster::raster(new_layer, layer=1),
           group=group_name,
-          options=leafletOptions(pane="layers"),
           colors=palNum
         )
     }
@@ -335,7 +334,6 @@ function(input, output, session) {
           data=new_layer,
           x=raster::raster(new_layer, layer=1),
           group=group_name,
-          options=leafletOptions(pane="layers"),
           colors=palNum
         ) %>%
         addMarkers(

ui.R

@@ -1,10 +1,6 @@
 library(shiny)
 library(shinyWidgets)
 library(leaflet)
-# To get the pane options in raster layers to work, install leaflet from 
-# https://github.com/rstudio/leaflet/tree/joe/feature/raster-options
-# see associated PR here: https://github.com/rstudio/leaflet/pull/692
-# can install directly with `remotes::install_github("rstudio/leaflet", ref="joe/feature/raster-options")`
 library(leaflet.extras)
 library(leaflegend)
 library(RColorBrewer)