Added xdebug for code coverage

Dockerfile

@@ -1,14 +1,20 @@
 FROM php:7.4-cli-alpine3.11
 
-RUN apk update && \
-    apk add --no-cache \
+RUN apk add --no-cache \
         libzip-dev \
         openssl-dev && \
     docker-php-ext-install -j$(nproc) \
         zip
 
 RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/bin/ --filename=composer
 
+RUN apk add --no-cache --virtual .phpize_deps $PHPIZE_DEPS && \
+    pecl install xdebug-2.9.2 && \
+    docker-php-ext-enable xdebug && \
+    rm -rf /usr/share/php7 && \
+    rm -rf /tmp/pear && \
+    apk del .phpize_deps
+
 ENV PATH /var/app/bin:/var/app/vendor/bin:$PATH
 
 WORKDIR /var/app