docs: fix typo on README.md

[calloc134]

Description

Fix typo on README.md.

-  unkownProp: 'hello there',
+  unknownProp: 'hello there',

Checklist

• the pull request title describes what this PR does (not a vague title like Update index.md)
• the pull request targets the default branch of the repository (develop)
• the code follows the established code style of the repository
  • npm run prettier:check passes
  • npm run lint:check passes
• tests are added for the changes I made (if any source code was modified)
• documentation added or updated
• I have run the project locally and verified that there are no errors