fixed build issues in Dockerfile.buildbase2

Author: Bernhard B

env/docker/Dockerfile.buildbase2

@@ -4,10 +4,12 @@ FROM bbernhard/imagemonkey-buildbase:latest
 
 ARG POSTGRES_CLIENT_VERSION
 
-RUN echo "deb http://deb.debian.org/debian stretch main" >> /etc/apt/sources.list
+RUN apt-get update && apt-get install -y --no-install-recommends \
+	curl gnupg ca-certificates \
+	&& rm -rf /var/lib/apt/lists/*
 
-RUN echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list \
-	&& wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
+RUN echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" >> /etc/apt/sources.list.d/pgdg.list
+RUN curl https://www.postgresql.org/media/keys/ACCC4CF8.asc | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/apt.postgresql.org.gpg >/dev/null
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
 	postgresql-client-${POSTGRES_CLIENT_VERSION} \