Some tests timing out

[guseggert]

This seems to be getting progressively worse over time...some tests are hanging and timing out waiting for propagation, see e.g. this run:

https://github.com/libp2p/go-libp2p-pubsub-router/runs/4035361341?check_suite_focus=true

[galargh]

I think it might be because of

go-libp2p-pubsub-router/pubsub.go

Line 91 in 1d5fc5c

rebroadcastInterval: time.Minute * 10,

. I don't know what the setting does exactly but it seems the tests either succeed after around 1 minute or 11 minutes.

To make the checks pass I have increased the go test timeout to 20 minutes - 9977e77

My commit can be reverted once the tests are able to configure rebroadcastInterval (assuming my guess is correct of course).