Update Dockerfile

pica-etherpad/Dockerfile

 # déclaration unique des variables d'environnement
-FROM node:10.11.0-slim as base
+FROM node:10-slim as base
 LABEL maintainer="antoine@barbare.me"
 
 ARG ETHERPAD_VERSION_BUILD=1.7.0
@@ -60,6 +60,7 @@ FROM base
 
 COPY entrypoint.sh /opt/etherpad-lite/entrypoint.sh
 RUN apt-get update && \
+    apt-get remove curl -y && \
     apt-get install -y mysql-client && \
     chmod +x /opt/etherpad-lite/entrypoint.sh && \
     mkdir -p /opt/etherpad-lite && \