Import howett.net/plist by its correct name

Also bumping the version to one with a go.mod.

vendor/howett.net/plist/util.go

@@ -0,0 +1,25 @@
+package plist
+
+import "io"
+
+type countedWriter struct {
+	io.Writer
+	nbytes int
+}
+
+func (w *countedWriter) Write(p []byte) (int, error) {
+	n, err := w.Writer.Write(p)
+	w.nbytes += n
+	return n, err
+}
+
+func (w *countedWriter) BytesWritten() int {
+	return w.nbytes
+}
+
+func unsignedGetBase(s string) (string, int) {
+	if len(s) > 1 && s[0] == '0' && (s[1] == 'x' || s[1] == 'X') {
+		return s[2:], 16
+	}
+	return s, 10
+}