Use "true" and "false" for more boolean values

Some IdPs (KPN) don't understand "1" and "0" as boolean values, but
insist that the standard says only "true" or "false" are allowed.

A previous commit (bcfc4d2) already fixed
several occurences, but it turned out there are more booleans hiding
in the metadata XML.

lib/Net/SAML2/AttributeConsumingService.pm

@@ -64,7 +64,7 @@ sub to_xml {
         $self->namespace,
         {
             index     => $self->index,
-            isDefault => $self->default,
+            isDefault => $self->default ? 'true' : 'false',
         },
         $xml->ServiceName($self->namespace, undef, $self->service_name),
         $self->_has_service_description ? $xml->ServiceDescription($self->namespace, undef, $self->service_description) : (),

lib/Net/SAML2/RequestedAttribute.pm

@@ -59,7 +59,7 @@ sub _build_attributes {
   my $self = shift;
 
   my %attrs = (
-    $self->required ? (isRequired => 1) : (),
+    $self->required ? (isRequired => 'true') : (),
     Name => $self->name,
     $self->_has_friendly ? (FriendlyName => $self->friendly_name) : (),
   );

t/02-create-sp.t

@@ -385,7 +385,7 @@ use URN::OASIS::SAML2 qw(:bindings :urn);
                 {
                     Binding  => BINDING_HTTP_ARTIFACT,
                     Location => 'https://foo.example.com/acs-http-artifact',
-                    isDefault => 0,
+                    isDefault => 'false',
                 }
             ],
             error_url => 'https://foo.example.com/error-url',
@@ -469,7 +469,7 @@ use URN::OASIS::SAML2 qw(:bindings :urn);
     my $acs  = get_single_node_ok($node,  '//md:AttributeConsumingService');
 
     is($acs->getAttribute('index'),     1, ".. index is 1");
-    is($acs->getAttribute('isDefault'), 0, "Not the default");
+    is($acs->getAttribute('isDefault'), 'false', "Not the default");
 
 
     my @child = $acs->childNodes();
@@ -486,7 +486,7 @@ use URN::OASIS::SAML2 qw(:bindings :urn);
     is($child[1]->getAttribute('FriendlyName'),
         'foo', ".. with the correct friendly name");
     is($child[1]->getAttribute('Name'),       'urn:foo:bar', ".. and name");
-    is($child[1]->getAttribute('isRequired'), '1', ".. and requiredness");
+    is($child[1]->getAttribute('isRequired'), 'true', ".. and requiredness");
 }
 
 {