Merge pull request #581 from tezrik/master

update code for php 8.0

Author: tezrik

.travis.yml

@@ -6,9 +6,6 @@ php:
   - 7.3
   - 7.4
   - 8.0
-matrix:
-    allow_failures:
-        - php: 8.0
 
 before_script:
   - composer self-update

composer.json

@@ -41,7 +41,7 @@
         "squizlabs/php_codesniffer": "^3.5",
         "symfony/var-dumper": "^5.1",
         "symfony/finder": "^5.1",
-        "phpunit/phpunit": "9.5.8",
+        "phpunit/phpunit": "^8.5",
         "friendsofphp/php-cs-fixer": "^3.0"
     },
     "suggest": {