ddclient: T6981: Upgrade ddclient to v4.0.0

Salsa doesn't have a v4.0.0 tag yet.
However commit ae21b1deee from the branch 'debian/next'
represent the tag for the release 4.0.0.

Author: indrajitr

scripts/package-build/ddclient/package.toml

@@ -1,4 +1,4 @@
 [[packages]]
 name = "ddclient"
-commit_id = "debian/3.11.2-1"
+commit_id = "ae21b1deee"
 scm_url = "https://salsa.debian.org/debian/ddclient"