package/libabseil-cpp: update BR2_PACKAGE_LIBABSEIL_CPP_ARCH_SUPPORTS
m68k is supported since version 20210324.0 and
https://github.com/abseil/abseil-cpp/commit/f3697b4fedc2d8f2311eaaebed051f6a44182bb2
s390x is supported since at least version 20180600 and
https://github.com/abseil/abseil-cpp/commit/a7e522daf1ec9cda69b356472f662142dd0c1215
sh is supported since version 20210324.0 and
https://github.com/abseil/abseil-cpp/commit/a2d7f453c635e90b356017dd47049b89407c2d88
sparc and sparc64 are supported since version 20210324.0 and
https://github.com/abseil/abseil-cpp/commit/3fcd00d7dddafe65ced638acca560105a414cba5
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>