[CI] Docker image updates (#1799)

polkadot/scripts/docker/Dockerfile

@@ -1,4 +1,4 @@
-FROM debian:stretch-slim
+FROM debian:buster-slim
 
 # metadata
 ARG VCS_REF

polkadot/scripts/docker/release.Dockerfile

@@ -0,0 +1,46 @@
+FROM debian:buster-slim
+
+# metadata
+ARG VCS_REF
+ARG BUILD_DATE
+
+LABEL io.parity.image.authors="devops-team@parity.io" \
+	io.parity.image.vendor="Parity Technologies" \
+	io.parity.image.title="parity/polkadot" \
+	io.parity.image.description="polkadot: a platform for web3" \
+	io.parity.image.source="https://github.com/paritytech/polkadot/blob/${VCS_REF}/scripts/docker/Dockerfile" \
+	io.parity.image.revision="${VCS_REF}" \
+	io.parity.image.created="${BUILD_DATE}" \
+	io.parity.image.documentation="https://github.com/paritytech/polkadot/"
+
+# show backtraces
+ENV RUST_BACKTRACE 1
+
+# install tools and dependencies
+RUN apt-get update && \
+		DEBIAN_FRONTEND=noninteractive apt-get upgrade -y && \
+		DEBIAN_FRONTEND=noninteractive apt-get install -y \
+			libssl1.1 \
+			ca-certificates \
+			curl \
+			gnupg && \
+		gpg --recv-keys --keyserver hkps://keys.mailvelope.com 9D4B2B6EB8F97156D19669A9FF0812D491B96798 && \
+		gpg --export 9D4B2B6EB8F97156D19669A9FF0812D491B96798 > /usr/share/keyrings/parity.gpg && \
+		echo 'deb [signed-by=/usr/share/keyrings/parity.gpg] https://releases.parity.io/deb release main' > /etc/apt/sources.list.d/parity.list && \
+		apt update && \
+		apt install polkadot && \
+# apt cleanup
+		apt-get autoremove -y && \
+		apt-get clean && \
+		find /var/lib/apt/lists/ -type f -not -name lock -delete
+
+USER polkadot
+
+# check if executable works in this container
+RUN /usr/bin/polkadot --version
+
+EXPOSE 30333 9933 9944
+VOLUME ["/polkadot"]
+
+ENTRYPOINT ["/usr/bin/polkadot"]
+