xdg-desktop-portal 1.0

• screenshot: Add a color picker api
• screencast: Bump the pipewire dependency to 0.2.1
• Improve --help output
• Small documentation improvements

$ sha256sum xdg-desktop-portal-1.0.tar.xz 
57e41b5842acca3fdd83211e41b80e6bc8e365f069dcc26dfcb22145f42ad787  xdg-desktop-portal-1.0.tar.xz