Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires squizlabs/php_codesniffer dev-master, found squizlabs/php_codesniffer[dev-feature/dont-ignore-internal-errors, dev-TEST/ghactions-revert-code-coverage-php-version, dev-feature/variable-sniffs-minor-performance-tweak, dev-feature/generators-dont-print-title-if-no-docs, dev-feature/add-security-file, dev-feature/3.x-metrics-for-switch-statements, dev-feature/773-safeguard-against-duplicate-test-markers, dev-feature/3769-improve-todo-fixme-sniffs, dev-feature/psr12-fileheader-more-modular-errorcode-spacing-after, dev-feature/pear-psr2-psr12-functioncallsignature-check-anon-classes, dev-4.x/feature/ci-prevent-issues-with-code-coverage, dev-phpcs-4.x/gitattributes-dont-ignore-test-framework-files, dev-phpcs-4.x/remove-external-tooling-sniffs, dev-phpcs-4.x/file-isreference-simplify, dev-phpcs-4.x/tokenizer-php-minor-tweak, dev-phpcs-4.x/3115-let-static-be-static, 1.4.2, ..., 1.5.x-dev, 2.0.0a1, ..., 2.9.x-dev, 3.0.0a1, ..., 3.11.2, 4.0.x-dev] but it does not match the constraint. Problem 2 - Root composer.json requires phpcsstandards/phpcsdevcs ^1.1 -> satisfiable by phpcsstandards/phpcsdevcs[1.1.0, ..., 1.1.6]. - phpcsstandards/phpcsdevcs[1.1.0, ..., 1.1.2] require squizlabs/php_codesniffer ^3.5.0 -> found squizlabs/php_codesniffer[3.5.0, ..., 3.11.2] but it conflicts with your root composer.json require (dev-master). - phpcsstandards/phpcsdevcs[1.1.3, ..., 1.1.6] require squizlabs/php_codesniffer ^3.6.2 -> found squizlabs/php_codesniffer[3.6.2, ..., 3.11.2] but it conflicts with your root composer.json require (dev-master).