Toggle fieldtype should augment to a boolean even when null.

src/Fieldtypes/Toggle.php

@@ -17,4 +17,9 @@ public function process($data)
     {
         return (bool) $data;
     }
+
+    public function augment($data)
+    {
+        return (bool) $data;
+    }
 }

tests/Fieldtypes/ToggleTest.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Tests\Fieldtypes;
+
+use Statamic\Fields\Field;
+use Statamic\Fieldtypes\Toggle;
+use Tests\TestCase;
+
+class ToggleTest extends TestCase
+{
+    /** @test */
+    public function it_augments_to_a_boolean()
+    {
+        $field = (new Toggle)->setField(new Field('test', ['type' => 'toggle']));
+
+        $this->assertFalse($field->augment(false));
+        $this->assertFalse($field->augment(null));
+        $this->assertTrue($field->augment(true));
+    }
+}