docs(Dialog): add allow-html prop (#6666)

src/dialog/README.md

@@ -133,6 +133,7 @@ export default {
 | closeOnPopstate `v2.0.5` | Whether to close when popstate | _boolean_ | `false` |
 | closeOnClickOverlay | Whether to close when click overlay | _boolean_ | `false` |
 | lockScroll | Whether to lock body scroll | _boolean_ | `true` |
+| allowHtml `v2.8.7` | Whether to allow HTML rendering in message | _boolean_ | `true` |
 | beforeClose | Callback before close,<br>call done() to close dialog,<br>call done(false) to cancel loading | (action: string, done: Function) => void | - |
 | transition `v2.2.6` | Transition, equivalent to `name` prop of [transtion](https://vuejs.org/v2/api/#transition) | _string_ | - |
 | getContainer | Return the mount node for Dialog | _string \| () => Element_ | `body` |
@@ -159,6 +160,7 @@ export default {
 | close-on-click-overlay | Whether to close when click overlay | _boolean_ | `false` |
 | lazy-render | Whether to lazy render util appeared | _boolean_ | `true` |
 | lock-scroll | Whether to lock background scroll | _boolean_ | `true` |
+| allow-html `v2.8.7` | Whether to allow HTML rendering in message | _boolean_ | `true` |
 | before-close | Callback before close,<br>call done() to close dialog,<br>call done(false) to cancel loading | (action: string, done: Function) => void | - |
 | transition `v2.2.6` | Transition, equivalent to `name` prop of [transtion](https://vuejs.org/v2/api/#transition) | _string_ | - |
 | get-container | Return the mount node for Dialog | _string \| () => Element_ | - |