add command validate

lib/App/Changelord.pm

@@ -59,5 +59,6 @@ sub run($self) {
 }
 
 subcommand 'schema' => 'App::Changelord::Command::Schema';
+subcommand 'validate' => 'App::Changelord::Command::Validate';
 
 'end of App::Changeman';

lib/App/Changelord/Command/Validate.pm

@@ -0,0 +1,39 @@
+package App::Changelord::Command::Validate;
+
+use 5.36.0;
+
+use Moo;
+use CLI::Osprey;
+
+use Path::Tiny;
+use JSON;
+use YAML::XS;
+use JSON::Schema::Modern;
+
+option json => (
+    is => 'ro',
+    default => 0,
+    doc => 'output schema as json',
+);
+
+sub run($self) {
+    local $YAML::XS::Boolean = 'boolean';
+
+    my $schema = path(__FILE__)->sibling('changelog-schema.yml')->slurp;
+
+    my $result = JSON::Schema::Modern->new(
+        output_format => 'detailed',
+    )->evaluate(
+        $self->parent_command->changelog,
+        YAML::XS::Load($schema),
+    );
+
+    return say "woo, changelog is valid!" if( $result eq 'valid' );
+
+
+    print $result;
+    die "\n";
+
+}
+
+'end of App::Changelog::Command::Validate';