chore: update editor v0.1.12 and format the readme (#2489)

frontend/appflowy_flutter/pubspec.lock

@@ -45,10 +45,10 @@ packages:
     dependency: "direct main"
     description:
       name: appflowy_editor
-      sha256: "5371e8aa78e6a5e5b5c958b1450958689755b5fd0e9862312ca423f7c0da9fcc"
+      sha256: "6f7d2b0b54ca1049cb396229549d228b5bbd7ea6d09f1f7325a20db2d7586a5f"
       url: "https://pub.dev"
     source: hosted
-    version: "0.1.10"
+    version: "0.1.12"
   appflowy_popover:
     dependency: "direct main"
     description:

frontend/appflowy_flutter/pubspec.yaml

@@ -42,7 +42,7 @@ dependencies:
     git:
       url: https://github.com/AppFlowy-IO/appflowy-board.git
       ref: a183c57
-  appflowy_editor: ^0.1.9
+  appflowy_editor: ^0.1.12
   appflowy_popover:
     path: packages/appflowy_popover