Bug: iOS VoiceOver announces stale content in headings

<!-- Please provide a clear and concise description of what the bug is. Include screenshots if needed. Please test using the latest version of the relevant React packages to make sure your issue has not already been fixed. --> React version: 17.0.2 ## Steps To Reproduce 1. Go to https://jeffreyatw.com/static/voiceover-react using iOS, enable VoiceOver 2. Swipe to first "Not clicked" h2, observe VoiceOver reads content correctly 3. Click the first "click me" button 4. Move VoiceOver's focus back to first h2, which is now "Clicked" 5. VoiceOver **incorrectly** reads it as "Not clicked, heading level 2" 6. Swipe to the second "Not clicked" h2, observe VoiceOver reads content correctly 7. Click the second "click me" button 8. Move VoiceOver's focus back to second h2, which is now "Clicked" 9. VoiceOver correctly reads it as "Clicked, heading level 2" <!-- Your bug will get fixed much faster if we can run your code and it doesn't have dependencies other than React. Issues without reproduction steps or code examples may be immediately closed as not actionable. --> Link to code example: https://jeffreyatw.com/static/voiceover-react <!-- Please provide a CodeSandbox (https://codesandbox.io/s/new), a link to a repository on GitHub, or provide a minimal code example that reproduces the problem. You may provide a screenshot of the application if you think it is relevant to your bug report. Here are some tips for providing a minimal example: https://stackoverflow.com/help/mcve. --> ## The current behavior VoiceOver reads the first h2 as "Not clicked, heading level 2". See attached video for more details: https://user-images.githubusercontent.com/266170/114103859-b4b51680-987e-11eb-82b9-0d785442c3ae.mp4 ## The expected behavior VoiceOver should read the first h2 as "Clicked, heading level 2"