Bump @openzeppelin/contracts from 3.4.1-solc-0.7-2 to 4.9.6

Bumps [@openzeppelin/contracts](https://github.com/OpenZeppelin/openzeppelin-contracts) from 3.4.1-solc-0.7-2 to 4.9.6.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-contracts/releases)
- [Changelog](https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/CHANGELOG.md)
- [Commits](OpenZeppelin/openzeppelin-contracts@v3.4.1-solc-0.7-2...v4.9.6)

---
updated-dependencies:
- dependency-name: "@openzeppelin/contracts"
  dependency-version: 4.9.6
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]