[matomo-web] apt-get update also required

[Andrea Veri <averi src gnome org>]

commit 55323ac3ea89e5b904e93596fc206ba6c0396c40
Author: Andrea Veri <averi redhat com>
Date:   Thu Sep 24 12:04:13 2020 +0200

    apt-get update also required

 matomo/Dockerfile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/matomo/Dockerfile b/matomo/Dockerfile
index 88bf7f3..73b4b49 100644
--- a/matomo/Dockerfile
+++ b/matomo/Dockerfile
@@ -2,7 +2,8 @@ FROM matomo:3-fpm
 
 USER root
 
-RUN apt-get install unzip
+RUN apt-get update && \
+    apt-get install unzip
 
 COPY ipa-ca.crt /usr/local/share/ca-certificates/ipa-ca.crt
 RUN update-ca-certificates