build: upgrade periph.io dependencies

vendor/periph.io/x/conn/v3/pin/pinreg/doc.go

@@ -0,0 +1,7 @@
+// Copyright 2016 The Periph Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+// Package pinreg is a registry for the physical headers (made up of pins) on
+// a host.
+package pinreg