Update fmt to 6.1.2

indra/deps/CMakeLists.txt

indra/llappearance/llavatarappearance.cpp

indra/llappearance/llpolymesh.cpp

indra/llappearance/llwearable.cpp

indra/llaudio/llaudioengine_fmodstudio.cpp

indra/llcharacter/llanimationstates.cpp

indra/llcommon/llapr.cpp

indra/llcommon/llerror.cpp

indra/llcommon/llinitparam.cpp

indra/llcommon/llinitparam.h

indra/llcommon/llmetricperformancetester.cpp

indra/llcommon/llmetricperformancetester.h

indra/llcommon/llqueuedthread.cpp

indra/llcommon/llsd.cpp

indra/llcommon/llsdparam.cpp

indra/llcommon/llstring.cpp

indra/llcommon/llstring.h

indra/llcommon/llsys.cpp

indra/llcommon/lltimer.cpp

indra/llcommon/lluri.cpp