Merge pull request #11 from akrabat/php8

Set minimum PHP version to 8.0

Author: akrabat

.gitignore

@@ -1,2 +1,3 @@
 build
 vendor
+.phpunit.result.cache

composer.json

@@ -18,10 +18,10 @@
         "psr/http-message": "^1.0"
     },
     "require-dev": {
-        "php": ">=7.0",
-        "phpunit/phpunit": "^6",
-        "squizlabs/php_codesniffer": "^2.3",
-        "zendframework/zend-diactoros": "^1.1"
+        "php": "^8.0",
+        "phpunit/phpunit": "^9.6",
+        "squizlabs/php_codesniffer": "^3.7",
+        "laminas/laminas-diactoros": "^2.24"
     },
     "autoload": {
         "psr-4": {