Change composer method due to the fact that we now use composer.lock files for live sites

tasks/deploy/gitcomposer.yml

@@ -21,7 +21,7 @@
 
 - name: "Run Composer"
   composer:
-    command='update'
+    command='install'
     working_dir='{{ webRoot }}'
     no_dev=yes
     optimize_autoloader=yes