vendor: add github.com/putdotio/go-putio for putio client

vendor/github.com/putdotio/go-putio/putio/doc.go

@@ -0,0 +1,11 @@
+// Package putio is the Put.io API v2 client for Go.
+//
+// The go-putio package does not directly handle authentication. Instead, when
+// creating a new client, pass an http.Client that can handle authentication for
+// you. The easiest and recommended way to do this is using the golang.org/x/oauth2
+// library, but you can always use any other library that provides an http.Client.
+//
+// Note that when using an authenticated Client, all calls made by the client will
+// include the specified OAuth token. Therefore, authenticated clients should
+// almost never be shared between different users.
+package putio