update phpunit to be php8 compatible

Author: smoench

Makefile

@@ -81,10 +81,7 @@ tc: bin/phpunit
 INFECTION=vendor-bin/infection/vendor/bin/infection
 tm:			 ## Runs Infection
 tm:	$(TU_BOX_DEPS) $(INFECTION)
-	cd vendor-bin/infection && \
- 	$(PHPNOGC) vendor/bin/infection \
- 		--only-covered \
- 		--configuration=../../infection.json.dist
+	cd vendor-bin/infection && $(PHPNOGC) vendor/bin/infection --only-covered
 
 .PHONY: e2e
 e2e:			 ## Runs all the end-to-end tests

composer.json

@@ -68,7 +68,7 @@
     "require-dev": {
         "bamarni/composer-bin-plugin": "^1.3",
         "mikey179/vfsstream": "^1.6",
-        "phpunit/phpunit": "^8.1",
+        "phpunit/phpunit": "9.2.*",
         "symfony/phpunit-bridge": "^4.2 || ^5.0"
     },
     "suggest": {