message: highlight breaking changes
diff: # 0.13.0
  -- adopt the new `Durability` API proposed in [RFC #6]
  +- **Breaking change:** adopt the new `Durability` API proposed in [RFC #6]
  - this replaces and generalizes the existing concepts of constants
  -- remove "volatile" queries -- instead, you can use
  +- **Breaking change:** remove "volatile" queries
  + - instead, create a normal query which invokes the
  `report_untracked_read` method on the salsa runtime
  - introduce "slots", an optimization to salsa's internal workings
  - document `#[salsa::requires]` attribute, which permits private dependencies
  