install(EXPORT) missing a means to specify package version
The find_package(.. VERSION ...) argument provides a means to specify a required version on importing. The FindPackageHandleStandardArgs modules provides a means to specify the available version in exporting. install(EXPORT ...) is really convenient for creating an export file
Unfortunately, install(EXPORT ...) does not appear to provide any means to specify the package version.
(When addressing this, it should probably cover other features of FindPackageHandleStandardArgs as well. I have not looked into those)