update CHANGELOG

CHANGELOG.md

@@ -9,6 +9,8 @@ _Jun 23, 2021_
 Big thanks to the 18 contributors who made this release possible. Here are some highlights ✨:
 
 - 🚀 We have completed all the [breaking changes](https://github.com/mui-org/material-ui/issues/20012). The plan to release 5.0.0-beta.0 is on July 1st and will start to promote its usage over v4.
+- 🎨 We have updated `Slider` to match current [material design spec](https://material.io/components/sliders).
+- 💡 `IconButton` now supports 3 sizes (`small, medium, large`). [See demo](/components/buttons/#sizes-2).
 
 ### `@material-ui/core@5.0.0-alpha.38`
 
@@ -172,6 +174,7 @@ Big thanks to the 18 contributors who made this release possible. Here are some
 - <!-- 02 --> [docs] Fix small PT typo fix: inciar -> iniciar (#26775) @brunocavalcante
 - <!-- 03 --> [I10n] Add Chinese (Hong Kong) (zh-HK) locale (#26637) @kshuiroy
 - <!-- 44 --> [l10n] Add sinhalese (siLK) locale (#26875) @pavinduLakshan
+- <!-- 39 --> [examples] Rename nextjs typescript theme from tsx to ts (#26862) @Izhaki
 
 ### Core
 
@@ -189,10 +192,6 @@ Big thanks to the 18 contributors who made this release possible. Here are some
 - <!-- 20 --> [core] Remove dependency on `@material-ui/private-theming` (#26793) @mnajdova
 - <!-- 15 --> [core] Remove dependency on `@material-ui/styled-engine` (#26792) @mnajdova
 
-### Starter
-
-- <!-- 39 --> [examples] Rename nextjs typescript theme from tsx to ts (#26862) @Izhaki
-
 All contributors of this release in alphabetical order: @ahmed-28, @brunocavalcante, @DanielBretzigheimer, @dijonkitchen, @dmrqx, @eps1lon, @Izhaki, @kshuiroy, @l10nbot, @michal-perlakowski, @michaldudak, @mnajdova, @oliviertassinari, @pavinduLakshan, @shadab14meb346, @siriwatknp, @tungdt-90, @varandasi
 
 ## 5.0.0-alpha.37