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/agent/agent.go b/cloud/agent/agent.go
index 028a7d6..c185b83 100644
--- a/cloud/agent/agent.go
+++ b/cloud/agent/agent.go
@@ -96,12 +96,12 @@
 		rootCAs.AddCert(caCert)
 	}
 
-	conn, err := grpc.Dial(agentInit.TakeoverInit.BmaasEndpoint, grpc.WithTransportCredentials(credentials.NewTLS(&tls.Config{
+	conn, err := grpc.NewClient(agentInit.TakeoverInit.BmaasEndpoint, grpc.WithTransportCredentials(credentials.NewTLS(&tls.Config{
 		Certificates: []tls.Certificate{*ephemeralCert},
 		RootCAs:      rootCAs,
 	})))
 	if err != nil {
-		return fmt.Errorf("error dialing BMaaS gRPC endpoint: %w", err)
+		return fmt.Errorf("error creating BMaaS gRPC client: %w", err)
 	}
 	c := bpb.NewAgentCallbackClient(conn)
 
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()