libsignon-glib is marked for autoremoval from testing

[Debian testing autoremoval watch]

libsignon-glib 1.12-2.1 is marked for autoremoval from testing on 2020-05-14

It is affected by these RC bugs:
952060: libsignon-glib: FTBFS: signon-auth-service.c:72:13: error: 
G_ADD_PRIVATE [-Werror]