Fixes #2789: Require minimum Composer API version. (#2790)

Author: grasmash

composer.json

@@ -15,7 +15,7 @@
     "license": "GPL-2.0-only",
     "require": {
         "php": ">=5.6",
-        "composer-plugin-api": "^1.0.0",
+        "composer-plugin-api": "^1.1.0",
         "composer/installers": "^1.2.0",
         "composer/semver": "^1.4",
         "consolidation/config": "^1.0.0",