Bump vaadin.version in /grid-renderers-collection-addon
Bump vaadin.version in /grid-renderers-collection-addon

Bumps `vaadin.version` from 8.8.0 to 8.12.4.

Updates `vaadin-server` from 8.8.0 to 8.12.4
- [Release notes](https://github.com/vaadin/framework/releases)
- [Commits](https://github.com/vaadin/framework/compare/8.8.0...8.12.4)

Updates `vaadin-client` from 8.8.0 to 8.12.4
- [Release notes](https://github.com/vaadin/framework/releases)
- [Commits](https://github.com/vaadin/framework/compare/8.8.0...8.12.4)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
vaadin/grid-renderers-collection-addon