Don't try deleting immutable folder

container/Dockerfile

@@ -62,10 +62,6 @@ RUN cd ~ && \
 	OTP_SECRET=precompile_placeholder SECRET_KEY_BASE=precompile_placeholder rails assets:precompile && \
 	yarn cache clean
 
-# Remove cached packages, break apt
-RUN rm -rf /var/cache && \
-	rm -rf /var/lib/apt/lists/*
-
 # Set the work dir and the container entry point
 WORKDIR /opt/mastodon
 ENTRYPOINT ["/tini", "--"]