Include project version bug fix in changelog

Author: smlindauer

CHANGELOG.md

@@ -11,6 +11,9 @@ v1.8.2 (2023-01-30)
  - Fixed an issue with `model_management.execute_model_workflow_definition()` where input values for
    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.
+   - Better handling for invalid project versions included.
 
 v1.8.1 (2023-01-19)
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