Adapt to the fact of AppImageUpdaterBridge apparent renaming into QAppImageUpdate

[d1vanov]

Through a CI build failure I learned that AppImageUpdaterBridge was renamed into QAppImageUpdate. As a short term fix I switched the CI build to use earlier version before the rename took place. But I need to adapt Quentier to the newer version.

[d1vanov]

Perhaps I can postpone this one until the new stable release of QAppImageUpdate.