[skip ci] Autogenerate README file.

Author: tedium-bot

README.md

@@ -151,6 +151,7 @@ Custom property | Description | Default
 `--paper-input-container-disabled` | Mixin applied to the container when it's disabled | `{}`
 `--paper-input-container-label` | Mixin applied to the label | `{}`
 `--paper-input-container-label-focus` | Mixin applied to the label when the input is focused | `{}`
+`--paper-input-container-label-floating` | Mixin applied to the label when floating | `{}`
 `--paper-input-container-input` | Mixin applied to the input | `{}`
 `--paper-input-container-underline` | Mixin applied to the underline | `{}`
 `--paper-input-container-underline-focus` | Mixin applied to the underline when the input is focused | `{}`