Update dev dep React in storybook-a11y-test to v18

Needs to match the major version that we're using in our main app or
else the versions of React will clash and the a11y test runner doesn't
work correctly.

packages/storybook-a11y-test/package.json

@@ -36,7 +36,7 @@
   },
   "devDependencies": {
     "@storybook/react": "^6.4.15",
-    "react": "^17.0.0"
+    "react": "^18.1.0"
   },
   "peerDependencies": {
     "@storybook/addon-a11y": ">=6.4.0",

yarn.lock

@@ -14349,7 +14349,7 @@ react-textarea-autosize@^8.3.0:
     use-composed-ref "^1.0.0"
     use-latest "^1.0.0"
 
-react@^17.0.0, react@^17.0.2:
+react@^17.0.2:
   version "17.0.2"
   resolved "https://registry.yarnpkg.com/react/-/react-17.0.2.tgz#d0b5cc516d29eb3eee383f75b62864cfb6800037"
   integrity sha512-gnhPt75i/dq/z3/6q/0asP78D0u592D5L1pd7M8P+dck6Fu/jJeL6iVVK23fptSUZj8Vjf++7wXA8UNclGQcbA==