ci: install libsodium, required by clusterer_controller

The multi-architecture builds fail on every job that builds modules:

  Makefile:18: *** clusterer_controller requires libsodium
  (install libsodium-dev / libsodium-devel).  Stop.

clusterer_controller hard-requires libsodium and stops the build when
it is missing, but libsodium-dev was never added to the CI package list
when the module was introduced.

Only the -qemu-cross jobs surface it: the plain -cross ones set
MAKE_TGT=opensips and build the core alone, so they never reach any
module and pass regardless.

Author: Lt-Flash

scripts/build/apt_requirements.txt

@@ -21,6 +21,7 @@ librabbitmq-dev
 libradcli-dev
 libsctp-dev
 libsnmp-dev
+libsodium-dev
 libsqlite3-dev
 libwolfssl-dev
 libxml2-dev