[tracker-oci-images/sam/asciidoc-fix] Disable interactive prompts in Ubuntu build

[Sam Thursfield <sthursfield src gnome org>]

commit 9b2e5d8a033f17495b876f8f4d6ec8f1892e432d
Author: Sam Thursfield <sam afuera me uk>
Date:   Sun Apr 5 19:29:13 2020 +0200

    Disable interactive prompts in Ubuntu build

 debian/prepare.sh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/debian/prepare.sh b/debian/prepare.sh
index f6aae53..92ddc66 100644
--- a/debian/prepare.sh
+++ b/debian/prepare.sh
@@ -2,8 +2,10 @@
 
 set -ex
 
-# Enable source repositories so we can use `apt-get build-dep`
+# Avoid interactive prompts!
+export DEBIAN_FRONTEND=noninteractive
 
+# Enable source repositories so we can use `apt-get build-dep`
 sed -Ei 's/^# deb-src /deb-src /' /etc/apt/sources.list
 apt-get -yq update && apt-get -yq upgrade