vendor: Mega update all dependencies

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4080

vendor/github.com/gogo/protobuf/GOLANG_CONTRIBUTORS

@@ -1,5 +0,0 @@
-The contributors to the Go protobuf repository:
-
-# This source code was written by the Go contributors.
-# The master list of contributors is in the main Go distribution,
-# visible at http://tip.golang.org/CONTRIBUTORS.