rsi 0.3.2

• Failed downloads and merges should now be handled a bit better. Thanks
  to @h-a-graham for #89 and to @lucas-johnson for #81.

• If composite = NULL and the resource has duplicated asset timestamps,
  get_stac_data() will now generate unique filenames (rather than saving
  multiple files to the same path). Thanks to @h-a-graham for #89 and #90.