Fixed spelling error.

Author: smlindauer

CHANGELOG.md

@@ -12,7 +12,7 @@ v1.8.2 (2023-01-30)
    workflow prompts were not correctly submitted.  Note that the `input=` parameter was renamed to
    `prompts=` to avoid conflicting with the built-in `input()`.
  - Fixed an issue with `pzmm.importModel.model_exists()` where project versions were incorrectly
-   compared, resulting in improper behavior with the project version already existed.
+   compared, resulting in improper behavior when the project version already existed.
    - Better handling for invalid project versions included.
 
 v1.8.1 (2023-01-19)