docs(reporters): junit env variables removed in v2 (#6841)

docs/guide/reporters.md

@@ -249,7 +249,7 @@ AssertionError: expected 5 to be 4 // Object.is equality
 </testsuites>
 ```
 
-The outputted XML contains nested `testsuites` and `testcase` tags. You can use the environment variables `VITEST_JUNIT_SUITE_NAME` and `VITEST_JUNIT_CLASSNAME` to configure their `name` and `classname` attributes, respectively. These can also be customized via reporter options:
+The outputted XML contains nested `testsuites` and `testcase` tags. You can use the reporter options to configure these attributes:
 
 ```ts
 export default defineConfig({