Bump minimum PHP version to ^8.0

Update symfony/console and symfony/yaml to ^6.0.

Author: tomzx

composer.json

@@ -20,12 +20,12 @@
 		"issues": "https://github.com/tomzx/php-semver-checker/issues"
 	},
 	"require": {
-		"php": ">=7.3",
+		"php": "^8.0",
 
 		"hassankhan/config": "^3.0",
 		"nikic/php-parser": "^4.0",
-		"symfony/console": "^4.0||^5.0",
-		"symfony/yaml": "^4.0||^5.0",
+		"symfony/console": "^6.0",
+		"symfony/yaml": "^6.0",
 		"tomzx/finder": "^0.2"
 	},
 	"require-dev": {
@@ -47,7 +47,7 @@
 	},
 	"config": {
 		"platform": {
-			"php": "7.3"
+			"php": "8.0.2"
 		}
 	},
 	"extra": {