fix(CI): missing go.sum entry for module providing package golang.org/x/net/proxy (imported by github.com/gorilla/websocket) on aggregator build

[JuArce]

When the CI tries to build the aggregator, it gets the following error

1.544 /root/go/pkg/mod/github.com/gorilla/websocket@v1.5.1/client.go:23:2: missing go.sum entry for module providing package golang.org/x/net/proxy (imported by github.com/gorilla/websocket); to add:
1.544 	go get github.com/gorilla/websocket@v1.5.1