Warning when building app docker

[pacoorozco]

Describe the bug
A warning is shown when app docker is build:

#############################################################################################################
#                                                                                                           #
#                                            W A R N I N G ! ! !                                            #
#                                                                                                           #
# You are using an unsupported method to get install-php-extensions!                                        #
#                                                                                                           #
# Please update the way you fetch it. Read the instrictions at                                              #
# https://github.com/mlocati/docker-php-extension-installer#usage                                           #
#                                                                                                           #
# For example, if you get this script by fetching                                                           #
# https://raw.githubusercontent.com/mlocati/docker-php-extension-installer/master/install-php-extensions    #
# replace it with                                                                                           #
# https://github.com/mlocati/docker-php-extension-installer/releases/latest/download/install-php-extensions #
#                                                                                                           #
# Sleeping for a while so you get bored of this and act ;)                                                  #
#                                                                                                           #
#############################################################################################################

To Reproduce
Steps to reproduce the behavior:

1. Execute docker-compose build
2. See error

Expected behavior
No warning should be shown