Bump github.com/mitchellh/mapstructure from 1.2.3 to 1.3.3

Bumps [github.com/mitchellh/mapstructure](https://github.com/mitchellh/mapstructure) from 1.2.3 to 1.3.3.
- [Release notes](https://github.com/mitchellh/mapstructure/releases)
- [Changelog](https://github.com/mitchellh/mapstructure/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mitchellh/mapstructure/compare/v1.2.3...v1.3.3

)

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