Just run on deploy[1 or 2]001: scap update-interwiki-cache.
Thank you.
Edit: just in case this task is handled by someone not familiar with this script, I forgot to mention that this plugin seems to live only on /srv/mediawiki-staging and that it'll ask for your gerrit shell name and HTTP password (see https://gerrit.wikimedia.org/r/#/settings/http-password to generate one). It'll commit the change and C+2 it afterwards. Once merged by jenkins, just answer 'yes' to the dialog and scap will continue with the deploy :-)