Bump the required CMake version to 2.8.12.
Bump the required CMake version to 2.8.12.

This is necessary to rely on the EXPORT_NAME target property.

simonwagner/grantlee,cutelyst/grantlee,simonwagner/grantlee,cutelyst/grantlee,simonwagner/grantlee,cutelyst/grantlee,simonwagner/grantlee,simonwagner/grantlee,cutelyst/grantlee,simonwagner/grantlee,cutelyst/grantlee