chore(deps-dev): bump @storybook/theming from 5.2.8 to 5.3.9

Bumps [@storybook/theming](https://github.com/storybookjs/storybook/tree/HEAD/lib/theming) from 5.2.8 to 5.3.9.
- [Release notes](https://github.com/storybookjs/storybook/releases)
- [Changelog](https://github.com/storybookjs/storybook/blob/next/CHANGELOG.md)
- [Commits](https://github.com/storybookjs/storybook/commits/v5.3.9/lib/theming)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

ui/storybook/package.json

@@ -18,7 +18,7 @@
     "@storybook/addons": "5.2.8",
     "@storybook/core-events": "5.2.8",
     "@storybook/react": "5.2.8",
-    "@storybook/theming": "5.2.8",
+    "@storybook/theming": "5.3.9",
     "@types/storybook__addon-info": "^4.1.2",
     "@types/storybook__react": "^4.0.2",
     "storybook-addon-styled-component-theme": "^1.2.5",