message: Add change log entry for pl locale [skip ci]
diff: @@ -142,6 +142,8 @@ for the list of changes made since `v2.0.0-alpha.1`.
  - [lv locale](https://github.com/date-fns/date-fns/pull/1175). Kudos to [@prudolfs](https://github.com/prudolfs).
  +- [pl locale was updated for v2](https://github.com/date-fns/date-fns/pull/1140). Thanks to [@Mutisz](https://github.com/Mutisz)!
  +
  - New locale-dependent week-numbering year helpers:
  - `getWeek`
  