linter: fix context package

internal/test/chainnotifier_mock.go

@@ -2,6 +2,7 @@ package test
 
 import (
 	"bytes"
+	"context"
 	"sync"
 	"time"
 
@@ -10,7 +11,6 @@ import (
 	"github.com/lightninglabs/lndclient"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/lnrpc/chainrpc"
-	"golang.org/x/net/context"
 )
 
 type mockChainNotifier struct {

internal/test/lightning_client_mock.go

@@ -1,6 +1,7 @@
 package test
 
 import (
+	"context"
 	"crypto/rand"
 	"encoding/hex"
 	"fmt"
@@ -17,7 +18,6 @@ import (
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"github.com/lightningnetwork/lnd/zpay32"
-	"golang.org/x/net/context"
 )
 
 type mockLightningClient struct {

internal/test/router_mock.go

@@ -1,9 +1,10 @@
 package test
 
 import (
+	"context"
+
 	"github.com/lightninglabs/lndclient"
 	"github.com/lightningnetwork/lnd/lntypes"
-	"golang.org/x/net/context"
 )
 
 type mockRouter struct {