add php8 support

Author: Koldo Picaza

composer.json

@@ -12,8 +12,14 @@
             "name": "kpicaza"
         }
     ],
+    "repositories": [
+        {
+            "type": "git",
+            "url": "https://github.com/antidot-framework/psr11-monolog"
+        }
+    ],
     "require": {
-        "php": "^7.4.0",
+        "php": "^7.4.0|^8.0",
         "psr/http-server-middleware": "^1.0",
         "psr/log": "^1.1"
     },
@@ -22,7 +28,7 @@
         "phpstan/phpstan": "^0.11.5 || ^0.12.0",
         "phpunit/phpunit": "^8.0 || ^9.0",
         "squizlabs/php_codesniffer": "^3.4",
-        "wshafer/psr11-monolog": "^3.0.0"
+        "wshafer/psr11-monolog": "@dev"
     },
     "autoload": {
         "psr-4": {