Delete vendored code and update CI to Go 1.13 (#158)

As the Go community transitions to using the modules ecosystem,
we want to only support one way of managing dependencies.
So this change moves to only using Go modules for dependency management.

This means that our effective minimum Go version increases to Go 1.11.
To account for this, we also update:
  - the documentation
  - Makefile
  - CI scripts

1 files changed, 0 insertions, 36 deletions

diff --git a/vendor/golang.org/x/sys/unix/sockcmsg_linux.go b/vendor/golang.org/x/sys/unix/sockcmsg_linux.go
deleted file mode 100644
index 6079eb4..0000000
--- a/vendor/golang.org/x/sys/unix/sockcmsg_linux.go
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Socket control messages
-
-package unix
-
-import "unsafe"
-
-// UnixCredentials encodes credentials into a socket control message
-// for sending to another process. This can be used for
-// authentication.
-func UnixCredentials(ucred *Ucred) []byte {
-	b := make([]byte, CmsgSpace(SizeofUcred))
-	h := (*Cmsghdr)(unsafe.Pointer(&b[0]))
-	h.Level = SOL_SOCKET
-	h.Type = SCM_CREDENTIALS
-	h.SetLen(CmsgLen(SizeofUcred))
-	*((*Ucred)(cmsgData(h))) = *ucred
-	return b
-}
-
-// ParseUnixCredentials decodes a socket control message that contains
-// credentials in a Ucred structure. To receive such a message, the
-// SO_PASSCRED option must be enabled on the socket.
-func ParseUnixCredentials(m *SocketControlMessage) (*Ucred, error) {
-	if m.Header.Level != SOL_SOCKET {
-		return nil, EINVAL
-	}
-	if m.Header.Type != SCM_CREDENTIALS {
-		return nil, EINVAL
-	}
-	ucred := *(*Ucred)(unsafe.Pointer(&m.Data[0]))
-	return &ucred, nil
-}