Bump installer's version to 3.x-beta

Author: yeegor

src/composer.json

@@ -12,7 +12,7 @@
     },
     "require": {
         "magento/product-community-edition": "2.3.5",
-        "scandipwa/installer": "2.0.1"
+        "scandipwa/installer": "3.0.*@beta"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "~2.13.0",
@@ -59,7 +59,7 @@
         }
     },
     "version": "2.3.1",
-    "minimum-stability": "stable",
+    "minimum-stability": "beta",
     "repositories": [
         {
             "type": "composer",