base-buster: Make sure to upgrade apt and dpkg first

The Let's Encrypt ISRG root has expired, and only recent versions of apt
support validating through the alternative chain. As the base image
we're building from is not up to date, we need to upgrade apt and dpkg
before running apt update on https sources.

base-buster/Dockerfile

@@ -13,7 +13,7 @@ RUN echo 'Explanation: profile: elasticsearch\nPackage: elasticsearch elasticsea
 RUN --mount=type=cache,id=apt-cache,target=/var/cache/apt --mount=type=cache,id=apt-lists,target=/var/lib/apt \
   export DEBIAN_FRONTEND=noninteractive && \
   apt-get --allow-releaseinfo-change update && \
-  apt-get install -y apt-transport-https curl ca-certificates gpg  && \
+  apt-get install -y apt-transport-https curl ca-certificates gpg apt dpkg && \
   echo deb [signed-by=/usr/share/keyrings/postgres-archive-keyring.gpg] http://apt.postgresql.org/pub/repos/apt/ buster-pgdg main > /etc/apt/sources.list.d/postgres.list && \
   curl -fsSL https://www.postgresql.org/media/keys/ACCC4CF8.asc | gpg --dearmor > /usr/share/keyrings/postgres-archive-keyring.gpg && \
   echo deb [signed-by=/usr/share/keyrings/nodejs-archive-keyring.gpg] https://deb.nodesource.com/node_12.x buster main > /etc/apt/sources.list.d/nodejs.list && \