Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpunit/phpunit 9.6.21 (exact version match: 9.6.21 or 9.6.21.0), found phpunit/phpunit[9.6.21] but the package is fixed to 9.5.18 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.

Process completed with exit code 2.