Try preventing docker layer caching from skipping apt-get update

Author: nmfretz

Dockerfile

@@ -6,8 +6,12 @@ ARG VERSION
 
 WORKDIR /build
 
-RUN apt-get update
-RUN apt-get install -y git clang cmake libsnappy-dev
+# RUN apt-get update
+# RUN apt-get install -y git clang cmake libsnappy-dev
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends git clang cmake libsnappy-dev && \
+    rm -rf /var/lib/apt/lists/*
 
 RUN git clone --branch $VERSION https://github.com/romanz/electrs .