EMP-1641 Allow any version of composer/installers

This allows using composer/installers v2 which is required if we want to update
to composer v2.

Author: elijahsummers

composer.json

@@ -27,7 +27,7 @@
   ],
   "require": {
     "php": ">=5.3",
-    "composer/installers": "~1.0",
+    "composer/installers": "*",
     "predis/predis": "v0.8.5"
   },
   "require-dev": {