Travis CI: Remove not-yet-released PHP 7.4
Travis CI: Remove not-yet-released PHP 7.4

PhrozenByte/Pico,picocms/Pico,picocms/Pico,TakamiChie/Pico,picocms/Pico,TakamiChie/Pico,PhrozenByte/Pico,TakamiChie/Pico,TakamiChie/Pico,PhrozenByte/Pico