Update dependencies

Author: schlessera

composer.json

@@ -33,7 +33,7 @@
         "wp-cli/shell-command": "^2",
         "wp-cli/super-admin-command": "^2",
         "wp-cli/widget-command": "^2",
-        "wp-cli/wp-cli": "dev-master"
+        "wp-cli/wp-cli": "^2.1.0"
     },
     "require-dev": {
         "roave/security-advisories": "dev-master",
@@ -51,7 +51,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "2.0.x-dev"
+            "dev-master": "2.1.x-dev"
         }
     },
     "autoload-dev": {