Há um problema de compatibilidade com o symfony/yam na hora de instalar pelo composer
composer require nfephp-org/sped-cte:dev-master
Problem 1
- Installation request for nfephp-org/sped-cte dev-master -> satisfiable by nfephp-org/sped-cte[dev-master].
- nfephp-org/sped-cte dev-master requires symfony/yaml ^3.3 -> satisfiable by symfony/yaml[3.3.x-dev, 3.4.x-dev, v3.3.0, v3.3.0-BETA1, v3.3.0-RC1, v3.3.1, v3.3.10, v3.3.11, v3.3.12, v3.3.13, v3.3.14, v3.3.15, v3.3.2, v3.3.3, v3.3.4, v3.3.5, v3.3.6, v3.3.7, v3.3.8, v3.3.9, v3.4.0, v3.4.0-BETA1, v3.4.0-BETA2, v3.4.0-BETA3, v3.4.0-BETA4, v3.4.0-RC1, v3.4.0-RC2, v3.4.1, v3.4.2, v3.4.3] but these conflict with your requirements or minimum-stability.
acredito que se vocês atualizarem a versão do yam no composer para a versão 4.0.3 resolve o problema