Move to vendor

Signed-off-by: Olivier Gambier <olivier@docker.com>

vendor/github.com/bugsnag/panicwrap/dup2.go

@@ -0,0 +1,11 @@
+// +build darwin dragonfly freebsd linux,!arm64 netbsd openbsd
+
+package panicwrap
+
+import (
+	"syscall"
+)
+
+func dup2(oldfd, newfd int) error {
+	return syscall.Dup2(oldfd, newfd)
+}