Version 3.14: AbstractAdapter.php contains deprecated methods

[aparnasreekumar13]

Bug Report

Q	A
Version(s)	3.14

Summary

Version 3.14: AbstractAdapter.php contains the following deprecated methods
contains, detach which are deprecated since ph p8.5 which should ideally be replaced with offsetExists and offsetUnset

public function removePlugin(Plugin\PluginInterface $plugin)
    {
        $registry = $this->getPluginRegistry();
        if ($registry->offsetExists($plugin)) {
            $plugin->detach($this->getEventManager());
            $registry->offsetUnset($plugin);
        }
        return $this;
    }

[froschdesign]

@aparnasreekumar13
Create a pull request and we will happy to review it!