Issue #2808121 by klausi, xjm, dawehner: Add PHPUnit initiative to MAINTAINERS.txt

core/MAINTAINERS.txt

@@ -506,6 +506,10 @@ Web services
 Workflow Initiative
 - Dick Olsson 'dixon_' https://www.drupal.org/u/dixon_
 
+PHPUnit Initiative
+- Klaus Purer 'klausi' https://www.drupal.org/u/klausi
+- Daniel Wehner 'dawehner' https://www.drupal.org/u/dawehner
+
 Provisional membership: None at this time.