rpg-select: Create a select input
In RinteRface/shinyRPG: What the Package Does (One Line, Title Case)

rpgSelect creates a dropdown select input. Whenever size is not NULL, it is displayed as a box.

updateRpgSelect allows to update a rpgSelect on the server.

rpgSelect(
  inputId,
  label,
  choices,
  selected = NULL,
  multiple = FALSE,
  size = NULL
)

updateRpgSelect(
  session = getDefaultReactiveDomain(),
  inputId,
  label = NULL,
  choices = NULL,
  selected = NULL
)

`inputId`	The `input` slot that will be used to access the value.
`label`	Display label for the control, or `NULL` for no label.
`choices`	List of values to select from. If elements of the list are named, then that name — rather than the value — is displayed to the user. It's also possible to group related inputs by providing a named list whose elements are (either named or unnamed) lists, vectors, or factors. In this case, the outermost names will be used as the group labels (leveraging the `<optgroup>` HTML tag) for the elements in the respective sublist. See the example section for a small demo of this feature.
`selected`	The initially selected value (or multiple values if `multiple = TRUE`). If not specified then defaults to the first value for single-select lists and no values for multiple select lists.
`multiple`	Is selection of multiple items allowed?
`size`	Number of items to show in the selection box; a larger number will result in a taller box. Not compatible with `selectize=TRUE`. Normally, when `multiple=FALSE`, a select input will be a drop-down list, but when `size` is set, it will be a box instead.
`session`	The `session` object passed to function given to `shinyServer`. Default is `getDefaultReactiveDomain()`.