Harbor: Clair updaters stuck in a loop due to change of alpine URL.

[reasonerjt]

Caused by: https://github.com/coreos/clair/issues/593
To mitigate the impact to CI we disabled the updaters in configuration, need to fix it before 1.6 release, either by a new release of Clair or we patch it in our build.

Also re-enable the updaters in configuration file.

[magerx]

sad

[reasonerjt]

Fixed in #5783 #5785 #5787