Update build environment from PHP 8.1 to PHP 8.5

Dockerfile

@@ -1,5 +1,5 @@
 # base PHP version for the build and final project
-FROM php:8.1-apache AS php-version
+FROM php:8.5-apache AS php-version
 
 # base composer stage to install dependencies
 FROM composer:2 AS vendor

README.md

@@ -9,7 +9,7 @@ Source code for the https://clue.engineering/ website.
 
 ### Install
 
-This project has a number of specific system requirements, including PHP 8.1+,
+This project has a number of specific system requirements, including PHP 8.5+,
 Composer, Docker Compose, and others.
 
 To ease development, we use Docker containers that include all development

composer.json

@@ -1,6 +1,6 @@
 {
     "require": {
-        "php": ">=8.1"
+        "php": ">=8.5"
     },
     "require-dev": {
         "sculpin/sculpin": "^3.3.2"
@@ -12,10 +12,5 @@
     },
     "replace": {
         "sculpin/sculpin-theme-composer-plugin": "1.0.2"
-    },
-    "config": {
-        "platform": {
-            "php": "8.1.8"
-        }
     }
 }