fix: tag relay with keep_alive (#2753)

Since the auto dialer was removed, we need to tag the relay with
`KEEP_ALIVE` to reconnect to it if we disconnect.

packages/transport-circuit-relay-v2/src/transport/reservation-store.ts

@@ -1,4 +1,4 @@
-import { TypedEventEmitter, setMaxListeners } from '@libp2p/interface'
+import { KEEP_ALIVE, TypedEventEmitter, setMaxListeners } from '@libp2p/interface'
 import { PeerMap } from '@libp2p/peer-collections'
 import { createBloomFilter } from '@libp2p/utils/filters'
 import { PeerQueue } from '@libp2p/utils/peer-queue'
@@ -249,6 +249,10 @@ export class ReservationStore extends TypedEventEmitter<ReservationStoreEvents>
             [RELAY_TAG]: {
               value: 1,
               ttl: expiration
+            },
+            [KEEP_ALIVE]: {
+              value: 1,
+              ttl: expiration
             }
           }
         })