[etherpad-web/oscp-backend] Re-attempt 1.8.3 upgrade

[Bartłomiej Piotrowski <bpiotrowski src gnome org>]

commit 38c7c7ee947bb64d20394a214a4567c57303393c
Author: Bartłomiej Piotrowski <bpiotrowski gnome org>
Date:   Wed May 13 11:48:04 2020 +0200

    Re-attempt 1.8.3 upgrade

 Dockerfile | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/Dockerfile b/Dockerfile
index 9040aee..9b99726 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,5 @@
 FROM centos/nodejs-10-centos7
-ARG ETHERPAD_VERSION="1.8.0"
+ARG ETHERPAD_VERSION="1.8.3"
 
 USER root
 
@@ -20,10 +20,10 @@ WORKDIR /opt/etherpad
 # Install a few default plugins:
 SHELL ["/usr/bin/scl", "enable", "rh-nodejs10"]
 RUN npm install ep_adminpads \
-    ep_font_family \
-    ep_font_size \
+    ep_delete_empty_pads \
+    ep_align \
+    ep_spellcheck \
     ep_headings2 \
-    ep_headings \
     ep_font_color \
     ep_markdown \
     ep_copy_paste_select_all \