fix mkdocs

Author: kurowski

Dockerfile

@@ -17,7 +17,7 @@ RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
     && docker-php-ext-install gd \
     && pecl install redis zip \
     && docker-php-ext-enable redis zip \
-    && apt-get install -y mariadb-client redis-tools mkdocs-material-extensions \
+    && apt-get install -y mariadb-client redis-tools mkdocs-material mkdocs-material-extensions \
     && apt-get install -y npm libgtk2.0-0 libgtk-3-0 libgbm-dev libnotify-dev libnss3 libxss1 libasound2 libxtst6 xauth xvfb \
     && apt-get install -y dnsutils glow pv \
     && apt-get clean -y && rm -rf /var/lib/apt/lists/*