Bump @tiptap/extension-superscript from 2.1.7 to 2.1.8

Bumps [@tiptap/extension-superscript](https://github.com/ueberdosis/tiptap/tree/HEAD/packages/extension-superscript) from 2.1.7 to 2.1.8.
- [Release notes](https://github.com/ueberdosis/tiptap/releases)
- [Changelog](https://github.com/ueberdosis/tiptap/blob/v2.1.8/packages/extension-superscript/CHANGELOG.md)
- [Commits](https://github.com/ueberdosis/tiptap/commits/v2.1.8/packages/extension-superscript)

---
updated-dependencies:
- dependency-name: "@tiptap/extension-superscript"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

package.json

@@ -35,7 +35,7 @@
         "@tiptap/extension-image": "^2.0.3",
         "@tiptap/extension-link": "^2.0.3",
         "@tiptap/extension-subscript": "^2.0.3",
-        "@tiptap/extension-superscript": "^2.0.3",
+        "@tiptap/extension-superscript": "^2.1.8",
         "@tiptap/extension-text-align": "^2.0.3",
         "@tiptap/extension-underline": "^2.0.3",
         "@tiptap/pm": "^2.0.3",