fix to build ubuntu20.04

Author: sreedhars

packaging/deb-in/CMakeLists.txt

@@ -93,6 +93,8 @@ ELSEIF(DEB_CODENAME STREQUAL "bionic")
   SET (DEB_PLATFORMRELEASE "ubuntu18.04")
 ELSEIF(DEB_CODENAME STREQUAL "eoan")
   SET (DEB_PLATFORMRELEASE "ubuntu19.10")
+ELSEIF(DEB_CODENAME STREQUAL "focal")
+  SET (DEB_PLATFORMRELEASE "ubuntu20.04")
 ELSE()
   MESSAGE(STATUS
     "Skipping deb packaging on unsupported platform ${DEB_CODENAME}.")