bump for silvershop 4

composer.json

@@ -5,14 +5,14 @@
     "type" : "silverstripe-vendormodule",
     "keywords" : ["silverstripe","shop","shopping cart","ecommerce","discount","coupons"],
     "require" : {
-        "silvershop/core": "^3"
+        "silvershop/core": "^4"
     },
     "authors": [{
       "name": "SilverShop Contributors",
       "homepage": "https://github.com/silvershop/silvershop-stock/graphs/contributors"
     }],
     "require-dev": {
-        "phpunit/phpunit": "^5.7",
+        "phpunit/phpunit": "^9.5",
         "squizlabs/php_codesniffer": "^3.0"
     },
     "scripts": {
@@ -25,7 +25,7 @@
     "minimum-stability": "dev",
     "extra": {
         "branch-alias": {
-            "dev-master": "2.x-dev"
+            "dev-main": "3.x-dev"
         },
         "expose": [
             "javascript",