Update Dockerfile

Dockerfile

@@ -4,7 +4,7 @@ LABEL maintainer "Patrick Chabrier <patrick.chabrier@inrae.fr>"
 
 RUN wget -O- http://neuro.debian.net/lists/xenial.us-ca.full | tee /etc/apt/sources.list.d/neurodebian.sources.list \
     && apt-key adv --recv-keys --keyserver hkp://pool.sks-keyservers.net:80 0xA5D32F012649A5A9 \
-    && sudo apt-get update
+    && apt-get update
 
 RUN apt-get install -y singularity-container