Optimize build pipeline to use prebuilt image.

Dockerfile

@@ -1,36 +1,15 @@
-FROM php:7.4-apache AS base
+#Composer part
+FROM composer:2 AS composer-build
 WORKDIR /var/www/html
 
-RUN apt-get update && \
-    apt-get install -y \
-    libicu-dev \
-    libgd-dev \
-    libonig-dev \
-    unzip && \
-    apt-get purge -y --auto-remove && \
-    apt-get clean && \
-    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* /usr/share/doc/*
-
-RUN docker-php-ext-install \
-    exif \
-    gd \
-    intl \
-    mbstring \
-    mysqli \
-    pdo_mysql
-
-FROM composer:2 AS build
-WORKDIR /var/www/html
-
-COPY composer.json .
-COPY composer.lock .
-RUN composer install --no-dev --no-scripts --ignore-platform-reqs
-
 COPY . .
+RUN composer install --no-dev --no-scripts --ignore-platform-reqs
 RUN composer dumpautoload --optimize
 
-FROM base AS final
-COPY --from=build /var/www/html /var/www/html
+#Use prebuilt image
+FROM cs-git.ddnss.de/docker/php-apache-7-4:latest AS final
+WORKDIR /var/www/html
+COPY --from=composer-build /var/www/html /var/www/html
 
 RUN sed -ri -e 's!/var/www/!/var/www/html!g' /etc/apache2/apache2.conf /etc/apache2/conf-available/*.conf
 RUN sed -ri -e 's!AllowOverride None!AllowOverride All!g' /etc/apache2/apache2.conf