Update doc/changes/changes_2.6.0.md

Co-authored-by: Mikhail Beck <mikhail.beck@exasol.com>

Author: ckunki

doc/changes/changes_2.6.0.md

@@ -4,7 +4,7 @@
 
 This release changes the strategy for deleting a SaaS database instance, as required by the changed behavior of the actual SaaS backend.
 
-Before, SAPIPY used only a fixed waiting time. In case of HTTP responses with status code 400 and their message containing "cluster is not in a proper state" SAPIPY now retries deleting the SaaS instance for max. 30 minutes.
+Before, SAPIPY used only a fixed waiting time. In case of HTTP responses with status code 400 and their messages containing the text "cluster is not in a proper state" SAPIPY now retries deleting the SaaS instance for max. 30 minutes.
 
 ## Bugfixes