🐛 FIX: Static Call to Non-Static Function

[asharirfan]

Hello guys 🙌

I have fixed a warning related to calling a non-static function statically.

[03-Oct-2018 15:04:53 UTC] PHP Deprecated:  Non-static method MainWPExampleExtension::renderPage() should not be called statically in /app/public/wp-content/plugins/mainwp-hello-world-extension/mainwp-example-extension.php on line 203
[03-Oct-2018 15:04:53 UTC] PHP Stack trace:
[03-Oct-2018 15:04:53 UTC] PHP   1. {main}() /app/public/wp-admin/admin.php:0
[03-Oct-2018 15:04:53 UTC] PHP   2. do_action() /app/public/wp-admin/admin.php:224
[03-Oct-2018 15:04:53 UTC] PHP   3. WP_Hook->do_action() /app/public/wp-includes/plugin.php:453
[03-Oct-2018 15:04:53 UTC] PHP   4. WP_Hook->apply_filters() /app/public/wp-includes/class-wp-hook.php:310
[03-Oct-2018 15:04:53 UTC] PHP   5. MainWPExampleExtensionActivator->settings() /app/public/wp-includes/class-wp-hook.php:286

Cheers!