Stop Moodle 3.9, 3.11 and 4.0 support

As informed, we are no longer supporting Moodle version 3.9 - 4.0, and it is recommended to upgrade to the latest versions.

version.php

@@ -27,5 +27,5 @@
 $plugin->component = 'tool_opencast';
 $plugin->release = 'v4.3-r1';
 $plugin->version = 2023112200;
-$plugin->requires = 2020061524; // Requires Moodle 3.9+.
+$plugin->requires = 2022112800; // Requires Moodle 4.1+.
 $plugin->maturity = MATURITY_STABLE;