Remove unnecessary instruction

Author: sibprogrammer

Dockerfile

@@ -1,5 +1,4 @@
 FROM php:7.3-cli
 
-RUN mkdir /opt/api-php-lib
 RUN docker-php-ext-install pcntl \
     && curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer