Add vendor

Specifically because I want to modify a dependency

vendor/github.com/muesli/cancelreader/cancelreader_unix.go

@@ -0,0 +1,18 @@
+//go:build solaris
+// +build solaris
+
+package cancelreader
+
+import (
+	"io"
+)
+
+// NewReader returns a reader and a cancel function. If the input reader is a
+// File, the cancel function can be used to interrupt a blocking read call.
+// In this case, the cancel function returns true if the call was canceled
+// successfully. If the input reader is not a File or the file descriptor
+// is 1024 or larger, the cancel function does nothing and always returns false.
+// The generic unix implementation is based on the posix select syscall.
+func NewReader(reader io.Reader) (CancelReader, error) {
+	return newSelectCancelReader(reader)
+}