devel/libnotify: update to 0.8.1 release (+)

New in 0.8.1:

• Keep version of bindings at 0.7 (#27) [Marco]

New in 0.8.0:

• Use Desktop Portal Notification when running confined (snap and flatpak) Now the library acts like a wrapper in such scenario, with some limited capabilities, but this will enforce security and user control over the allowed notifications. [Marco]
• notify-send: Handles SIGINT gracefully, closing waiting notification [Marco]
• Use NotifyClosedReason enum as closed reason return value [Marco]
• Bump dependency on GLib 2.38 [Marco]
• Various introspection docs improvements and fixes [Marco]