Add Material UI v5 to migration guide

Adds information to the migration guide regarding the Material UI v5 update.

Also slightly restructures the migration guide entries to order them according to
importance.

closes #1850

Signed-off-by: Lukas Boll lukas-bool@web.de

Author: LukasBoll

MIGRATION.md

@@ -2,20 +2,6 @@
 
 ## Migrating to JSON Forms 3.0 for React users
 
-### Removal of React Material extended renderer set
-
-Previously we maintained a separate 'extended' renderer set to not force all consumers of JSON Forms to consume the Material UI lab dependency.
-With the update to Material UI v5 the lab dependency became more important as it also contains all date and time pickers.
-Therefore we now require the lab dependency and removed the no longer needed extended renderer set.
-
-If you consumed the extended renderer set then just revert to the normal renderer set.
-There should not be any behavior changes.
-
-### Removal of Class Components in React Material
-
-With Version 3.0 of JSON Forms we removed all React Material class components.
-Please check whether you extended any of our base renderers in your adaptation.
-
 ### Removal of JSON Schema $Ref Parser
 
 With version 3.0 of JSON Forms, we removed the `json-schema-ref-parser` dependency within the core package.
@@ -79,6 +65,25 @@ function App() {
 
 For more information have a look at our [ref-resolving](https://jsonforms.io/docs/ref-resolving) docs page.
 
+### Update to Material UI v5 in React Material
+
+Material UI was updated from version 4 to version 5 which introduced a lot of breaking changes.
+To update your application see the official Material UI [migration guide](https://mui.com/guides/migration-v4/).
+
+### Removal of React Material extended renderer set
+
+Previously we maintained a separate 'extended' renderer set to not force all consumers of JSON Forms to consume the Material UI lab dependency.
+With the update to Material UI v5 the lab dependency became more important as it also contains all date and time pickers.
+Therefore we now require the lab dependency and removed the no longer needed extended renderer set.
+
+If you consumed the extended renderer set then just revert to the normal renderer set.
+There should not be any behavior changes.
+
+### Removal of Class Components in React Material
+
+All React Material class components were refactored to functional components.
+Please check whether you extended any of our base renderers in your adaptation.
+
 ## Migrating to JSON Forms 2.5 for Angular users
 
 The JsonFormsAngularService is not provided in the root anymore.