[master] 8e45ba9fa circleci: Explicitly install cpio on DPKG systems

[Dridi Boukelmoune]

commit 8e45ba9faba203d6516175f521b44569be5dd612
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Wed Jun 10 21:21:43 2020 +0200

    circleci: Explicitly install cpio on DPKG systems
    
    This is understandably no longer present on the buster base docker
    image, but I'm not adding this to installation instructions in the
    documentation because I hope to remove that dependency before the
    next release.

diff --git a/.circleci/config.yml b/.circleci/config.yml
index ee4c63b37..fe106028c 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -173,6 +173,7 @@ jobs:
                     automake \
                     build-essential \
                     ca-certificates \
+                    cpio \
                     graphviz \
                     libedit-dev \
                     libjemalloc-dev \