Update test environment to fix tests on legacy PHP 7.2 with PHPUnit 8.5

Author: clue

.github/workflows/ci.yml

@@ -32,7 +32,4 @@ jobs:
           extensions: zlib
           coverage: xdebug
       - run: composer install
-      - run: vendor/bin/phpunit --coverage-text
-        if: ${{ matrix.php >= 7.3 }}
-      - run: vendor/bin/phpunit --coverage-text -c phpunit.xml.legacy
-        if: ${{ matrix.php < 7.3 }}
+      - run: vendor/bin/phpunit --coverage-text ${{ matrix.php < 7.3 && '-c phpunit.xml.legacy' || '' }}

composer.json

@@ -16,7 +16,7 @@
         "react/stream": "^1.2"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.6 || ^6.5",
+        "phpunit/phpunit": "^9.6 || ^8.5 || ^6.5",
         "react/event-loop": "^1.2"
     },
     "autoload": {