bump google.golang.org/grpc v1.23.0

full diff: https://github.com/grpc/grpc-go/compare/v1.20.1...v1.23.0

This update contains security fixes:

- transport: block reading frames when too many transport control frames are queued (grpc/grpc-go#2970)
  - Addresses CVE-2019-9512 (Ping Flood), CVE-2019-9514 (Reset Flood), and CVE-2019-9515 (Settings Flood).

Other changes can be found in the release notes:
https://github.com/grpc/grpc-go/releases/tag/v1.23.0

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor/google.golang.org/grpc/picker_wrapper.go

@@ -120,6 +120,14 @@ func (bp *pickerWrapper) pick(ctx context.Context, failfast bool, opts balancer.
 			bp.mu.Unlock()
 			select {
 			case <-ctx.Done():
+				if connectionErr := bp.connectionError(); connectionErr != nil {
+					switch ctx.Err() {
+					case context.DeadlineExceeded:
+						return nil, nil, status.Errorf(codes.DeadlineExceeded, "latest connection error: %v", connectionErr)
+					case context.Canceled:
+						return nil, nil, status.Errorf(codes.Canceled, "latest connection error: %v", connectionErr)
+					}
+				}
 				return nil, nil, ctx.Err()
 			case <-ch:
 			}