Update Dockerfile-71

php7.1-xdebug instead of php-xdebug instead.
apt-get update needed therefore

workspace/Dockerfile-71

@@ -132,8 +132,8 @@ RUN echo "" >> ~/.bashrc && \
 ARG INSTALL_XDEBUG=false
 RUN if [ ${INSTALL_XDEBUG} = true ]; then \
     # Load the xdebug extension only with phpunit commands
-    apt-get install -y --force-yes php-xdebug && \
-    sed -i 's/^;//g' /etc/php/7.1/cli/conf.d/20-xdebug.ini && \
+    apt-get update && \
+    apt-get install -y --force-yes php7.1-xdebug && \    sed -i 's/^;//g' /etc/php/7.1/cli/conf.d/20-xdebug.ini && \
     echo "alias phpunit='php -dzend_extension=xdebug.so /var/www/vendor/bin/phpunit'" >> ~/.bashrc \
 ;fi
 # ADD for REMOTE debugging