Merge pull request #3670 from Laravel-Backpack/select-nested-field-fix-output

fix echoing of select2 nested

Author: tabacitu

src/resources/views/crud/fields/select2_nested.blade.php

@@ -16,7 +16,7 @@ function echoSelect2NestedEntry($entry, $field, $current_value) {
             } else {
                 $selected = '';
             }
-            echo "<option value='".$entry->getKey()."' '.$selected.'>";
+            echo '<option value="'.$entry->getKey().'"'.$selected.'>';
             echo str_repeat("-", (int)$entry->depth > 1 ? (int)$entry->depth - 1 : 0).' '.$entry->{$field['attribute']};
             echo "</option>";
         }