Upgrade dependencies for PHP 8 compatibility (#430)

* Upgrade dependencies for PHP 8 compatibility

* PHP 8 compatibility

Author: Greg Bowler

composer.json

@@ -12,7 +12,7 @@
 		"ext-posix": "*",
 		"ext-dom": "*",
 		"ext-json": "*",
-		"php": ">=7.4",
+		"php": ">=8.0",
 		"phpgt/build": "^1.0",
 		"phpgt/cli": "^1.3",
 		"phpgt/config": "^1.0",
@@ -31,7 +31,7 @@
 		"phpgt/sync": "^1.2",
 
 		"psr/http-server-middleware": "^1.0",
-		"willdurand/negotiation": "^2.3"
+		"willdurand/negotiation": "^3.0"
 	},
 
 	"require-dev": {