Update composer to suit latest changes

composer.json

@@ -19,7 +19,6 @@
         {
             "name": "Luke Towers",
             "email": "octobercms@luketowers.ca",
-            "homepage": "https://luketowers.ca",
             "role": "Maintainer"
         }
     ],
@@ -27,12 +26,10 @@
         "issues": "https://github.com/octobercms/october/issues",
         "forum": "https://octobercms.com/forum/",
         "docs": "https://octobercms.com/docs/",
-        "irc": "irc://irc.freenode.net/october",
-        "chat": "https://discord.gg/gEKgwSZ",
         "source": "https://github.com/octobercms/october"
     },
     "require": {
-        "php": "^7.2",
+        "php": ">=7.2",
         "ext-mbstring": "*",
         "ext-openssl": "*",
         "october/rain": "dev-wip/laravel-6 as 1.0",
@@ -43,19 +40,18 @@
         "wikimedia/composer-merge-plugin": "dev-master"
     },
     "require-dev": {
-        "fzaninotto/faker": "^1.9",
         "phpunit/phpunit": "^8.0|^9.0",
-        "dms/phpunit-arraysubset-asserts": "^0.1.0",
-        "meyfa/phpunit-assert-gd": "^2.0",
+        "fzaninotto/faker": "~1.9",
         "squizlabs/php_codesniffer": "3.*",
-        "jakub-onderka/php-parallel-lint": "^1.0"
+        "jakub-onderka/php-parallel-lint": "^1.0",
+        "meyfa/phpunit-assert-gd": "^2.0.0",
+        "dms/phpunit-arraysubset-asserts": "^0.1.0"
     },
     "autoload-dev": {
         "classmap": [
             "tests/concerns/InteractsWithAuthentication.php",
             "tests/fixtures/backend/models/UserFixture.php",
             "tests/TestCase.php",
-            "tests/UiTestCase.php",
             "tests/PluginTestCase.php"
         ]
     },
@@ -69,7 +65,7 @@
             "php artisan package:discover"
         ],
         "test": [
-            "phpunit --stop-on-failure --prepend ./vendor/october/rain/src/Support/helpers.php"
+            "phpunit --stop-on-failure"
         ],
         "lint": [
             "parallel-lint --exclude vendor --exclude storage --exclude tests/fixtures/plugins/testvendor/goto/Plugin.php ."
@@ -79,7 +75,10 @@
         ]
     },
     "config": {
-        "preferred-install": "dist"
+        "preferred-install": "dist",
+        "platform": {
+            "php": "7.2"
+        }
     },
     "minimum-stability": "dev",
     "prefer-stable": true,