Update deps

Signed-off-by: Jack Cherng <jfcherng@gmail.com>

Author: jfcherng

.travis.yml

@@ -14,7 +14,7 @@ before_install:
   - pecl install -f ast
 
 install:
-  - rm -f composer.lock  # temporary fix for PHPUnit 8
+  - rm -f composer.lock  # workaround for testing among different PHP versions
   - composer install --prefer-dist --no-progress
 
 script:

composer.json

@@ -39,7 +39,7 @@
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^2.16",
         "phan/phan": "^2.5",
-        "phpunit/phpunit": "^7.5 || ^8 || ^9",
+        "phpunit/phpunit": ">=7 <10",
         "squizlabs/php_codesniffer": "^3.5"
     },
     "config": {