Failed to deploy Laravel project in DigitalOcean App Platform

Hello! I tried to deploy a Laravel project in Digitalocean App Platform but it fails with following error:

• Installation request for phpseclib/bcmath_compat 1.0.6 -> satisfiable by phpseclib/bcmath_compat[1.0.6]. phpseclib/phpseclib 2.0.30 requires php >=5.3.3 -> satisfiable by php[7.1.33, 7.2.26, 7.2.27, 7.2.28, 7.2.29, 7.2.30, 7.2.31, 7.2.32, 7.2.33, 7.2.34, 7.3.13, 7.3.14, 7.3.15, 7.3.16, 7.3.17, 7.3.18, 7.3.19, 7.3.20, 7.3.21, 7.3.22, 7.3.23, 7.3.24, 7.3.25, 7.3.26, 7.4.10, 7.4.11, 7.4.12, 7.4.13, 7.4.14, 7.4.2, 7.4.3, 7.4.4, 7.4.5, 7.4.6, 7.4.7, 7.4.8, 7.4.9, 8.0.0, 8.0.1].

I see in github project of bcmath_compat (https://github.com/phpseclib/bcmath_compat) that in Heroku environment they suggest to execute command:

composer require phpseclib/bcmath_compat:1.0.4

I insert it in build command of Digitalocean App Platform but problem persist. Any suggestion? Thanks!