chore(deps): bump gear-core from v1.0.2 to v1.2.0 in /contracts

Bumps [gear-core](https://github.com/gear-tech/gear) from v1.0.2 to v1.2.0.
- [Release notes](https://github.com/gear-tech/gear/releases)
- [Changelog](https://github.com/gear-tech/gear/blob/master/docker/Dockerfile-release)
- [Commits](gear-tech/gear@d02d306...80fffbc)

---
updated-dependencies:
- dependency-name: gear-core
  dependency-type: direct:production
...

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