'For DEB', so why do they install it by default?
Only redundant here, and a minor QA offence.

--- a/CMakeLists.txt	2018-02-14 09:42:31.000000000 +0100
+++ b/CMakeLists.txt	2019-09-30 23:47:11.529985366 +0200
@@ -102,9 +102,4 @@
 set(CPACK_PACKAGE_FILE_NAME
     "${CPACK_PACKAGE_NAME}-${CPACK_PACKAGE_VERSION}-${CPACK_PACKAGE_RELEASE}.${CMAKE_SYSTEM_PROCESSOR}")
 
-# For DEB
-install(FILES ${CPACK_RESOURCE_FILE_LICENSE}
-        DESTINATION share/doc/${CPACK_PACKAGE_NAME}
-        RENAME copyright)
-
 include(CPack)