Update Perl binding

Author: terryburton

libs/bindings/perl/example.pl

@@ -1,6 +1,7 @@
-#!/usr/bin/perl -w
+#!/usr/bin/perl
 
 use strict;
+use warnings;
 use postscriptbarcode;
 
 my $bwipp;

libs/bindings/perl/t/run_example.t

@@ -1,6 +1,7 @@
-#!/usr/bin/perl -w
+#!/usr/bin/perl
 
 use strict;
+use warnings;
 
 print "1..1\n";
 require 'example.pl';  ## no critic (RequireBarewordIncludes)