Follow keyboard version should also pick up copyright and author

**Is your feature request related to a problem? Please describe.**
When updating a keyboard, it is extra work to update copyright information in the .kps file.

**Describe the solution you'd like**
The "Package version follows keyboard version" check box in Keyman Developer could also pick up (in addition to the
version number) the copyright and author information as well.

**Describe alternatives you've considered**
Manual edit

**Additional context**
Additionally, if the "Package version follows keyboard version" check box is ticked when the .kps file is closed, please delete any version number, copyright or author information before writing out the .kps file. (Otherwise this stale information hangs around in the file.)