Fixed casefolding for case insensitivity

Change-Id: Ibad88cb8158cc9f4884330250a5464b750f00a1c
diff --git a/Makefile.PL b/Makefile.PL
index 56ab8ee..966bda5 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -28,6 +28,7 @@
     'File::Temp'      => 0,
     'Directory::Iterator' => 0,
     'Benchmark'       => 0,
+    'Unicode::CaseFold' => 1.00,
     'Carp'            => 0,
     'strict'          => 0,
     'warnings'        => 0,