Deprecations findings

[rikardow]

Hi, thanks for the great work on this plugin

We found a couple of deprecations in the codebase, here's the list

1. File: mod/equella/oauthlocallib.php
   Line: 260
   Message: Function openssl_free_key() is deprecated since PHP 8.0.
   Type: warning

2. File: mod/equella/oauthlocallib.php
   Line: 280
   Message: Function openssl_free_key() is deprecated since PHP 8.0.
   Type: warning

Thank you very much for your efforts

[edalex-ian]

Thanks for the heads up there rikardow, we'll see if we can scheduled some time to review this. If you are able to raise a PR, that'd also be very help.

Thanks.