Add PHP8

- update README.md with latest PHP information
- update composer.json to support PHP 7.3 to PHP8
  - active support for PHP 7.2 ended 6 Dec 2020
  - PHP8 was released 26-Nov-2020
  - update the dependencies
- PHPUnit now version 9.5 and config file updated
- ECS now version 9.3 and config file changed from `ecs.yaml` to `ecs.php`

ApprovalTest removed, in line with latest readme, all set for refactoring :)

Tested with PHP 7.3, 7.4 and 8.0 one failing "fixme" != "foo" test!

php/composer.json

@@ -2,7 +2,7 @@
     "name": "emilybache/gilded-rose-refactoring-kata",
     "description": "A kata to practice refactoring, tests and polymorphism",
     "require": {
-        "php": "^7.2"
+        "php": "^7.3 || ^8.0"
     },
     "autoload": {
         "psr-4": {
@@ -15,11 +15,11 @@
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "^8.0",
-        "phpstan/phpstan": "^0.12.23",
-        "phpstan/phpstan-phpunit": "^0.12.8",
-        "symplify/easy-coding-standard": "^7.3",
-        "symplify/phpstan-extensions": "^7.3",
+        "phpunit/phpunit": "^9.5",
+        "phpstan/phpstan": "^0.12.85",
+        "phpstan/phpstan-phpunit": "^0.12.18",
+        "symplify/easy-coding-standard": "^9.3",
+        "symplify/phpstan-extensions": "^9.3",
         "approvals/approval-tests": "^1.4"
     },
     "scripts": {
@@ -28,8 +28,8 @@
         "test": "phpunit",
         "tests": "phpunit",
         "test-coverage": "phpunit --coverage-html build/coverage",
-        "check-cs": "ecs check src tests --ansi",
-        "fix-cs": "ecs check src tests --fix --ansi",
+        "check-cs": "ecs check",
+        "fix-cs": "ecs check --fix",
         "phpstan": "phpstan analyse --ansi"
     }
 }