Bump version to 0.8.1

Bump version to 0.8.1

There were lots of changes on this version. The summary at
ChangeLog contains a sanitized version of it.

It should be noticed that the next version will likely bring
an uAPI incompatible change. Unfortunately, UEFI CPER record
trace for ARM processor is currently incomplete upstream.

Rasdaemon gained support for an extended arm trace event that
supports all fields of the CPER record, but it depends on a
patch that it is not upstreamed yet.

While looked on such patches, there are some changes needed
to get it merged, meaning that future versions of rasdaemon
may not be compatible with the downstream patch anymore.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>