Bug 1898762 - copy windows en-US full installers for nightly to the timestamped -l10n directory. r=releng-reviewers,taskgraph-reviewers,gabriel

This makes it possible for bouncer to point at any locale's installer in
the same place (see bug 1895249).

Differential Revision: https://phabricator.services.mozilla.com/D211560

taskcluster/gecko_taskgraph/manifests/firefox_nightly.yml

@@ -376,6 +376,7 @@ mapping:
             by-locale:
                 en-US:
                     - ${year}/${month}/${upload_date}-${branch}
+                    - ${year}/${month}/${upload_date}-${branch}-l10n
                     - latest-${branch}
                     - latest-${branch}-l10n
                 default: