Update Button

Problem

Flatpak applications can now be updated in the background. If a new version of Builder is installed, we might want to let the user know so they can restart Builder with the bug fixes and improvements.

Goals

• Provide a "Builder has been updated" button in the header bar when a new version has been installed

Anti-Goals

Affected Modules

1. libide-gui for a new button and monitor code (perhaps in IdeApplication)

Interfaces

No new interfaces are required.

Risks

Low risk, but should ensure to only run when Builder is running from Flatpak.
GLib version has to be raised to 2.60 if G_APPLICATION_ALLOW_REPLACE must be used.

Implementation Details