Give hint about the latest compatible template version

#### Reason/Context
When using a template that's not compatible with the current version of the generator, we get an error with a message saying it's not compatible.

#### Description
It would be great to get an error message saying which is the latest compatible version of the template in regards to the generator version the user is using.

No file or test is named in the issue. Start by locating the generator path that raises the incompatible-template error, then trace how generator and template versions are compared; done means a regression test demonstrates that the error reports the latest compatible template version.

Written by the indexing model from the issue text.