Test against PHP 8.0 instead of nightly
Test against PHP 8.0 instead of nightly

jmikola/mongo-php-library-prototype,jmikola/mongo-php-library,mongodb/mongo-php-library,jmikola/mongo-php-library,10gen-labs/mongo-php-library-prototype,mongodb/mongo-php-library,jmikola/mongo-php-library,jmikola/mongo-php-library,mongodb/mongo-php-library,mongodb/mongo-php-library