Update versions [ci skip]

Version 0.8.1

fix gtk-sys version

Upgrade crate version

Update versions [ci skip]

Update versions [ci skip]

remove duplicated lines

Merge pull request gtk-rs#641 from gtk-rs/crate-release-update

[release] merging crate-release-update into crate

Merge pull request gtk-rs#598 from gtk-rs/crate-release-update

[release] merging crate-release-update into crate

Merge pull request gtk-rs#276 from gtk-rs/serious_branch

Serious commit