Upgraded pg client tools to version 10 to support my postgresql server 10

Dockerfile

@@ -6,6 +6,12 @@ LABEL maintainer="Paulino Padial <github.com/ppadial>"
 # Environment variables (with default values)
 ENV CRON_LOG_LEVEL=8
 
+# PostgreSQL 10 repository install
+RUN apt-get update && apt-get upgrade -y && \
+    apt-get install -y wget lsb-release && \
+    wget -q https://www.postgresql.org/media/keys/ACCC4CF8.asc -O - | apt-key add - && \
+    echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" >> /etc/apt/sources.list.d/pgdg.list
+
 # Packages installation
 RUN apt-get update && apt-get upgrade -y && \
     apt-get install -y autopostgresqlbackup cron bzip2 gzip postgresql-client && \