Add use warnings;

Since `use strict;` is already there, add this as well to fix another
Kwalitee issue.

lib/SVN/Notify.pm

@@ -1,6 +1,7 @@
 package SVN::Notify;
 
 use strict;
+use warnings;
 require 5.006_000;
 use constant WIN32  => $^O eq 'MSWin32';
 use constant PERL58 => $] > 5.007_000;

lib/SVN/Notify/Alternative.pm

@@ -1,6 +1,7 @@
 package SVN::Notify::Alternative;
 
 use strict;
+use warnings;
 use SVN::Notify ();
 
 $SVN::Notify::Alternative::VERSION = '2.87';

lib/SVN/Notify/Filter/Trac.pm

@@ -1,6 +1,7 @@
 package SVN::Notify::Filter::Trac;
 
 use strict;
+use warnings;
 use Text::Trac;
 use SVN::Notify;
 

lib/SVN/Notify/HTML.pm

@@ -1,6 +1,7 @@
 package SVN::Notify::HTML;
 
 use strict;
+use warnings;
 use HTML::Entities;
 use SVN::Notify ();
 

lib/SVN/Notify/HTML/ColorDiff.pm

@@ -1,6 +1,7 @@
 package SVN::Notify::HTML::ColorDiff;
 
 use strict;
+use warnings;
 use HTML::Entities;
 use SVN::Notify::HTML ();