Add missing KF5Auth link

It is so far brought in implicitly by KConfigWidgets,
but missing when that is built without Auth support.
Signed-off-by: Andreas Sturmlechner <asturm@gentoo.org>

src/CMakeLists.txt

@@ -270,6 +270,7 @@ target_compile_definitions(kalarm_bin PRIVATE -DVERSION="${KALARM_VERSION}")
 
 target_link_libraries(kalarm_bin
     kalarmprivate
+    KF5::Auth
     KF5::Codecs
     KF5::ConfigCore
     KF5::Completion