[etherpad-web/oscp-backend] Update to develop branch, install libreoffice-common

[Bartłomiej Piotrowski <bpiotrowski src gnome org>]

commit 97e68ea11896b1eaecda16dd5967f685e8436998
Author: Bartłomiej Piotrowski <bpiotrowski gnome org>
Date:   Wed May 13 19:33:22 2020 +0200

    Update to develop branch, install libreoffice-common

 Dockerfile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/Dockerfile b/Dockerfile
index f9e7583..3247f92 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,11 +1,11 @@
 FROM node:10-buster-slim
 
-ENV ETHERPAD_VERSION 1.8.3
+ENV ETHERPAD_VERSION 770c1c80b7a57360e22579dbc0d00be7a385b533
 ENV NODE_ENV production
 
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y \
-    ca-certificates curl unzip mariadb-client --no-install-recommends && \
+    ca-certificates curl unzip mariadb-client soffice --no-install-recommends && \
     rm -r /var/lib/apt/lists/* /var/cache/apt/*
 RUN update-ca-certificates