Albert v0.16.4 released

Hotfix for #959

[albert]

• Fix tab order. Closes #866
• Update stale.yml

[plugins]

• [chromium] Chromium v1.1

[python]

• [docker] New extension prototype
• [timer] Use dbus instead of notify-send
• [units] v1.2 including to time conversion

Check the GitHub repositories for details.