* Add the PHP PPA.
* Specify the version when invoking the php CLI.
* Specify the version in package names.
* Update paths to 8.0 (using a variable in the setup scripts).
* Update z-push's php-xsl dependency to php8.0-xml.
* php-json is now built-into PHP.
Although PHP 8.1 is the stock version in Ubuntu 22.04, it's not supported by Nextcloud yet, and it likely will never be supported by the the version of Nextcloud that succeeds the last version of Nextcloud that supports PHP 7.2, and we have to install the next version so that an upgrade is permitted, so skipping to PHP 8.1 may not be easily possible.
Joshua Tauberer
Pascal Garber
Jan Schulz-Hofen
Filip Weiss
Helmuth Gronewold