update news

Author: cpsievert

NEWS.md

@@ -13,6 +13,10 @@
 * **plotly** objects can now be serialized and unserialized in different environments (i.e., you can now use `saveRDS()` to save an object as an rds file and restore it on another machine with `readRDS()`). Note this object is *dynamically* linked to JavaScript libraries, so one should take care to use consistent versions of **plotly** when serializing and unserializing (#1376).
 * The `plotly_example()` will now attempt to open the source file(s) used to run the example. Set `edit = FALSE` to prevent the source file(s) from opening.
 
+## CHANGES
+
+* The 'collaborate' button no longer appears in the modebar, and as a result, the `config()` function no longer has a `collaborate` argument.
+
 ## BUG FIXES
 
 * `subplot()` now bumps annotation `xref`/`yref` anchors correctly (#1181).