Support proxy certs in vino

Users behind firewalls may be unable to build the vino
image as a result of OpenSSL errors stemming from certificates used
with the proxy. To address this, the images impacted have been
updated to copy the proxy certificate from vino/certs into
the image and run update-ca-certificates command. This is the same
behavior that already exists in the airshipctl and sip images.

Signed-off-by: Alexander Hughes <Alexander.Hughes@pm.me>
Change-Id: Ibef36a6967bb82868be3b5bf9860dce4a46c79cb

Dockerfile

@@ -3,6 +3,14 @@ FROM gcr.io/gcp-runtimes/go1-builder:1.13 as builder
 
 ENV PATH "/usr/local/go/bin:$PATH"
 
+# Inject custom root certificate authorities if needed.
+# Docker does not have a good conditional copy statement and requires that a
+# source file exists to complete the copy function without error. Therefore, the
+# README.md file will be copied to the image every time even if there are no
+# .crt files.
+COPY ./certs/* /usr/local/share/ca-certificates/
+RUN update-ca-certificates
+
 WORKDIR /workspace
 # Copy the Go Modules manifests
 COPY go.mod go.mod

certs/README.md

@@ -0,0 +1,8 @@
+# Additional Docker image root certificate authorities
+
+If you require additional certificate authorities for your Docker image:
+* Add ASCII PEM encoded .crt files to this directory
+  * The files will be copied into your docker image at build time.
+
+To update manually copy the `.crt` files to `/usr/local/share/ca-certificates/`
+and run `sudo update-ca-certificates`.