CHANGELOG.markdown in image_optim-0.30.0 vs CHANGELOG.markdown in image_optim-0.31.0

@@ -1,8 +1,13 @@
 # ChangeLog
 
 ## unreleased
 
+## v0.31.0 (2021-10-03)
+
+* Add support for Oxipng [#167](https://github.com/toy/image_optim/issues/167) [#190](https://github.com/toy/image_optim/pull/190) [@oblakeerickson](https://github.com/oblakeerickson)
+* Fix `TypeError: can't convert ImageOptim::Timer into Float` with Ruby 3 [#194](https://github.com/toy/image_optim/pull/194) [@yahonda](https://github.com/yahonda)
+
 ## v0.30.0 (2021-05-11)
 
 * Add `timeout` option to restrict maximum time spent on every image [#21](https://github.com/toy/image_optim/issues/21) [#148](https://github.com/toy/image_optim/pull/148) [#149](https://github.com/toy/image_optim/pull/149) [#162](https://github.com/toy/image_optim/pull/162) [#184](https://github.com/toy/image_optim/pull/184) [#189](https://github.com/toy/image_optim/pull/189) [@tgxworld](https://github.com/tgxworld) [@oblakeerickson](https://github.com/oblakeerickson) [@toy](https://github.com/toy)
 
 ## v0.29.0 (2021-04-28)