Install less in Dockerfile

Author: dandavison

etc/docker/ubuntu.Dockerfile

@@ -1,7 +1,7 @@
 FROM ubuntu:20.04
 
 RUN apt-get update && \
-    apt-get install -y curl git
+    apt-get install -y curl git less
 
 RUN curl -OL https://github.com/dandavison/delta/releases/download/0.4.5/delta-0.4.5-x86_64-unknown-linux-gnu.tar.gz && \
     tar -xzvf delta-0.4.5-x86_64-unknown-linux-gnu.tar.gz