REL: v0.6.4 (#201)

Author: kmuehlbauer

docs/history.md

@@ -1,9 +1,9 @@
 # History
 
-## Development version (2024-08-23)
+## 0.6.4 (2024-08-30)
 
 FIX: Notebooks are now conforming to ruff's style checks by [@rcjackson](https://github.com/rcjackson), ({pull}`199`) by [@rcjackson](https://github.com/rcjackson).
-FIX: use dict.get() to retrieve attribute key and return "None" if not available [@kmuehlbauer](https://github.com/kmuehlbauer), ({pull}`200`) by [@kmuehlbauer](https://github.com/kmuehlbauer)
+FIX: use dict.get() to retrieve attribute key and return "None" if not available, ({pull}`200`) by [@kmuehlbauer](https://github.com/kmuehlbauer)
 
 ## 0.6.3 (2024-08-13)