Update Known Issues for potential solution

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackware-id.org>
Upgrade base/ to 1.8.0

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackware-id.org>
Upgrade extra/ to 1.8.0

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackware-id.org>
Update documentation for MATE 1.8

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackware-id.org>