Stop violating not null constraint

Fixes this error:

ERROR: failed to process declarative jobset test:inputs,
DBIx::Class::Storage::DBI::_dbh_execute(): DBI Exception: DBD::Pg::st
execute failed: ERROR:  null value in column "emailoverride" violates
not-null constraint

src/lib/Hydra/Helper/AddBuilds.pm

@@ -57,7 +57,7 @@ sub updateDeclarativeJobset {
                 name => $name,
                 type => $data->{type}
             };
-            $row->{emailresponsible} = $data->{emailresponsible} if defined $data->{emailresponsible};
+            $row->{emailresponsible} = $data->{emailresponsible} // 0;
             my $input = $jobset->jobsetinputs->create($row);
             $input->jobsetinputalts->create({altnr => 0, value => $data->{value}});
         }