Bump phpunit dependency for internal testing

https://stackoverflow.com/questions/70455395/phpunit-cannot-acquire-reference-to-globals

Author: juampi92

.github/workflows/run-tests.yml

@@ -14,7 +14,7 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         php: [8.0, 8.1, 8.2]
-        phpunit: [^8.3, 9.*, 10.*]
+        phpunit: [^8.5.23, 9.*, 10.*]
         stability: [prefer-lowest, prefer-stable]
         exclude:
           - php: 8.0