Add ca-certificates to container image

Author: summerwind

Dockerfile

@@ -1,5 +1,13 @@
+FROM ubuntu:18.04 AS base
+
+RUN apt update \
+  && apt install -y ca-certificates
+
+#############################
+
 FROM scratch
 
 COPY ./cloudevents-feed-notifier /bin/cloudevents-feed-notifier
+COPY --from=base /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
 
 ENTRYPOINT ["/bin/cloudevents-feed-notifier"]