Tests vagrant: fix Composer version
Tests vagrant: fix Composer version

Refs #1972

3liz/lizmap-web-client,nboisteault/lizmap-web-client,laurentj/lizmap-web-client,nboisteault/lizmap-web-client,rldhont/lizmap-web-client,rldhont/lizmap-web-client,3liz/lizmap-web-client,laurentj/lizmap-web-client,nboisteault/lizmap-web-client,rldhont/lizmap-web-client,3liz/lizmap-web-client,3liz/lizmap-web-client,nboisteault/lizmap-web-client,rldhont/lizmap-web-client,laurentj/lizmap-web-client,laurentj/lizmap-web-client