chore(deps-dev): bump mobx from 6.10.2 to 6.13.5

Bumps [mobx](https://github.com/mobxjs/mobx) from 6.10.2 to 6.13.5.
- [Release notes](https://github.com/mobxjs/mobx/releases)
- [Commits](https://github.com/mobxjs/mobx/compare/mobx@6.10.2...mobx@6.13.5)

---
updated-dependencies:
- dependency-name: mobx
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]