Fix installer verification on plesk (#2380)

Author: Anilm3

dockerfiles/verify_packages/installer/test_install_on_plesk.sh

@@ -8,7 +8,7 @@ set -e
 new_version="0.82.0"
 generate_installers "${new_version}"
 
-prefix="/opt/plesk/php/8.0"
+prefix="/opt/plesk/php/8.1"
 "$prefix/bin/php" ./build/packages/datadog-setup.php --php-bin=all
 
 assert_ddtrace_version "${new_version}" "$prefix/bin/php"