[#5082] Increase tsa/client keepalive timeout

- Changed the timeout from 5s to 5m as 5s might be too aggresive for
  remote workers that don't have reliable connections.

  This timeout is to detect the condition where we observed SentRequest
  to hang indefinitely, which can still be reliably detected with a
  timeout of 5m.

Signed-off-by: Sameer Vohra <vohra.sam@gmail.com>

tsa/client.go

@@ -109,7 +109,7 @@ func (client *Client) Register(ctx context.Context, opts RegisterOptions) error
 	defer sshClient.Close()
 
 	keepAliveInterval := time.Second * 5
-	keepAliveTimeout := time.Second * 5
+	keepAliveTimeout := time.Minute * 5
 	go KeepAlive(ctx, sshClient, tcpConn, keepAliveInterval, keepAliveTimeout)
 
 	gardenListener, err := sshClient.Listen("tcp", gardenForwardAddr)