message: update README firebase card images
diff: <p align="center">
  <a href="https://firebase.google.com/products/firestore">
  - <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/firestore.png" alt="Cloud Firestore" width="33%" />
  + <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/firestore.png" alt="Cloud Firestore" width="32%" />
  </a>
  <a href="https://firebase.google.com/products/auth">
  - <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/authentication.png" alt="Firebase Authentication" width="33%" />
  + <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/authentication.png" alt="Firebase Authentication" width="32%" />
  </a>
  <a href="https://firebase.google.com/products/functions">
  - <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/functions.png" alt="Firebase Functions" width="33%" />
  + <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/functions.png" alt="Firebase Functions" width="32%" />
  </a>
  <a href="https://firebase.google.com/products/hosting">
  - <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/hosting.png" alt="Firebase Hosting" width="33%" />
  + <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/hosting.png" alt="Firebase Hosting" width="32%" />
  </a>
  <a href="https://firebase.google.com/products/storage">
  - <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/storage.png" alt="Firebase Storage" width="33%" />
  + <img src="https://github.com/AntlerVC/firetable/wiki/images/firebase/storage.png" alt="Firebase Storage" width="32%" />
  </a>
  </p>
  