treewide: replace deprecated grpc.Dial with grpc.NewClient

Change-Id: I925912ca1ee01d547fd9c1813eb083a2cd9a590a
Reviewed-on: https://review.monogon.dev/c/monogon/+/3858
Reviewed-by: Jan Schär <jan@monogon.tech>
Tested-by: Jenkins CI
diff --git a/cloud/bmaas/server/agent_callback_service_test.go b/cloud/bmaas/server/agent_callback_service_test.go
index e0ec9d0..a055d1d 100644
--- a/cloud/bmaas/server/agent_callback_service_test.go
+++ b/cloud/bmaas/server/agent_callback_service_test.go
@@ -65,9 +65,9 @@
 		if err != nil {
 			t.Fatalf("could not generate ephemeral credentials: %v", err)
 		}
-		conn, err := grpc.Dial(s.ListenPublic, grpc.WithTransportCredentials(creds))
+		conn, err := grpc.NewClient(s.ListenPublic, grpc.WithTransportCredentials(creds))
 		if err != nil {
-			t.Fatalf("Dial failed: %v", err)
+			t.Fatalf("NewClient failed: %v", err)
 		}
 		defer conn.Close()
 
@@ -143,9 +143,9 @@
 		if err != nil {
 			t.Fatalf("could not generate ephemeral credentials: %v", err)
 		}
-		conn, err := grpc.Dial(s.ListenPublic, grpc.WithTransportCredentials(creds))
+		conn, err := grpc.NewClient(s.ListenPublic, grpc.WithTransportCredentials(creds))
 		if err != nil {
-			t.Fatalf("Dial failed: %v", err)
+			t.Fatalf("NewClient failed: %v", err)
 		}
 		defer conn.Close()