Add NEWS bullet

Author: teunbrand

NEWS.md

@@ -1,5 +1,7 @@
 # ggplot2 (development version)
 
+* Binned scales are now compatible with `trans = "date"` and `trans = "time"` 
+  (@teunbrand, #4217).
 * Fixed a regression in `geom_hex()` where aesthetics were replicated across 
   bins (@thomasp85, #5037 and #5044)
 * Fixed spurious warning when `weight` aesthetic was used in `stat_smooth()`