changing INSTALL just to be more readable

INSTALL.md

@@ -38,8 +38,7 @@ vim conf/Conf.php
 ```bash
 git clone https://gitlab.mbb.univ-montp2.fr/jlopez/wicopa.git
 # you need to have wicopa.sql here
-wget http://web.mbb.univ-montp2.fr/download/wicopa.sql.gz
-gunzip -d wicopa.sql.gz
+wget http://web.mbb.univ-montp2.fr/download/wicopa.sql.gz && gunzip -d wicopa.sql.gz
 
 sudo docker-compose up --build
 # you can access to it at http://127.0.0.1:8000