dh_grantlee is a debhelper program that looks for *.so files of grantlee plugins, installed in
/usr/lib/$DEB_HOST_MULTIARCH/grantlee or /usr/lib/$DEB_HOST_MULTIARCH/qt5/plugins/grantlee, under a
subdirectory named "MAJOR.MINOR" (e.g. 5.2): in case any is found, a proper dependency
"grantlee5-templates-MAJOR-MINOR" dependency is added to the ${grantlee:Depends} substitution variable.
This is needed because Grantlee loads plugins for templates only in subdirectories named after its
"MAJOR.MINOR" version.
You can pass --withgrantlee to dh(1) to make it automatically call dh_grantlee after dh_install, or add
the "dh-sequence-grantlee" build dependency.