apt tweak

Dockerfile

@@ -2,8 +2,9 @@ FROM ruby:2.3-slim
 MAINTAINER WPScan Team <team@wpscan.org>
 
 RUN DEBIAN_FRONTEND=noninteractive && \
+  rm -rf /var/lib/apt/lists/* && \
   apt-get update && \
-  apt-get -qq -y install curl git ca-certificates openssl libcurl4-openssl-dev libxml2 libxml2-dev libxslt1-dev build-essential procps
+  apt-get --no-install-recommends -qq -y install curl git ca-certificates openssl libcurl4-openssl-dev libxml2 libxml2-dev libxslt1-dev build-essential procps
 
 RUN useradd -d /wpscan wpscan
 RUN echo "gem: --no-ri --no-rdoc" > /etc/gemrc