Add release note

releasenotes/notes/add-dataframe-curve-data-a8905c450748b281.yaml

@@ -0,0 +1,16 @@
+---
+features:
+  - |
+    :class:`.ScatterTable` is introduced as a drop-in replacement of :class:`.CurveData`.
+    
+    This is a data format to store intermediate data in curve analysis, built on top of
+    the pandas DataFrame. Each table row corresponds to a single data point, 
+    and the table contains all data points generated by the :class:`.CurveAnalysis`.
+    All properties and methods of :class:`.CurveData` are implemented for backward compatibility,
+    but these will be removed in the future release.
+developer:
+  - |
+    :meth:`.CurveAnalysis._create_figures` method is added to the curve analysis base class.
+    A curve analysis subclass can overwrite this method to customize the output figures.
+    The method is called with the :class:`.ScatterTable` containing all intermediate data points 
+    generated during the curve analysis.