chore: add php 8 support

composer.json

@@ -18,17 +18,14 @@
 		"forum": "https://discourse.pressbooks.org/"
 	},
 	"config": {
-		"platform": {
-			"php": "7.4"
-		},
-    "sort-packages": true,
+		"sort-packages": true,
 		"allow-plugins": {
 			"composer/installers": true,
 			"dealerdirect/phpcodesniffer-composer-installer": true
 		}
 	},
 	"require": {
-		"php": ">=7.4",
+		"php": "^7.4|8.0.*",
 		"composer/installers": "^2",
 		"phpcompatibility/php-compatibility": "^9.3",
 		"pressbooks/mix": "^2.1",

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "4d7cd01dc8e472d2a68d952060a21d78",
+    "content-hash": "bca254bf292cf20628d024e2b7bf1d91",
     "packages": [
         {
             "name": "composer/installers",
@@ -2857,11 +2857,8 @@
     "prefer-stable": false,
     "prefer-lowest": false,
     "platform": {
-        "php": ">=7.4"
+        "php": "^7.4|8.0.*"
     },
     "platform-dev": [],
-    "platform-overrides": {
-        "php": "7.4"
-    },
     "plugin-api-version": "2.3.0"
 }