Updated Dockerfiles to include ffmpeg

contrib/docker/Dockerfile.apache

@@ -5,7 +5,7 @@ ARG COMPOSER_CHECKSUM="1f210b9037fcf82670d75892dfc44400f13fe9ada7af9e787f93e50e3
 
 RUN apt-get update \
  && apt-get install -y --no-install-recommends apt-utils \
- && apt-get install -y --no-install-recommends git gosu \
+ && apt-get install -y --no-install-recommends git gosu ffmpeg \
       optipng pngquant jpegoptim gifsicle libpq-dev libsqlite3-dev locales zip unzip libzip-dev libcurl4-openssl-dev \
       libfreetype6 libicu-dev libjpeg62-turbo libpng16-16 libxpm4 libwebp6 libmagickwand-6.q16-6 \
       libfreetype6-dev libjpeg62-turbo-dev libpng-dev libxpm-dev libwebp-dev libmagickwand-dev mariadb-client\

contrib/docker/Dockerfile.fpm

@@ -4,7 +4,7 @@ ARG COMPOSER_CHECKSUM="1f210b9037fcf82670d75892dfc44400f13fe9ada7af9e787f93e50e3
 
 RUN apt-get update \
  && apt-get install -y --no-install-recommends apt-utils \
- && apt-get install -y --no-install-recommends git gosu \
+ && apt-get install -y --no-install-recommends git gosu ffmpeg \
       optipng pngquant jpegoptim gifsicle libpq-dev libsqlite3-dev locales zip unzip libzip-dev libcurl4-openssl-dev \
       libfreetype6 libicu-dev libjpeg62-turbo libpng16-16 libxpm4 libwebp6 libmagickwand-6.q16-6 \
       libfreetype6-dev libjpeg62-turbo-dev libpng-dev libxpm-dev libwebp-dev libmagickwand-dev mariadb-client\