Bump cia.project.versions.vaadin from 8.12.0.alpha1 to 8.12.0.alpha2
Bump cia.project.versions.vaadin from 8.12.0.alpha1 to 8.12.0.alpha2

Bumps `cia.project.versions.vaadin` from 8.12.0.alpha1 to 8.12.0.alpha2.

Updates `vaadin-themes` from 8.12.0.alpha1 to 8.12.0.alpha2
- [Release notes](https://github.com/vaadin/framework/releases)
- [Commits](https://github.com/vaadin/framework/compare/8.12.0.alpha1...8.12.0.alpha2)

Updates `vaadin-compatibility-server` from 8.12.0.alpha1 to 8.12.0.alpha2
- [Release notes](https://github.com/vaadin/framework/releases)
- [Commits](https://github.com/vaadin/framework/compare/8.12.0.alpha1...8.12.0.alpha2)

Updates `vaadin-maven-plugin` from 8.12.0.alpha1 to 8.12.0.alpha2
- [Release notes](https://github.com/vaadin/maven-plugin/releases)
- [Commits](https://github.com/vaadin/maven-plugin/compare/8.12.0.alpha1...8.12.0.alpha2)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
Hack23/cia,Hack23/cia,Hack23/cia,Hack23/cia