Update CHANGELOG.rst with modification in state estimation code

CHANGELOG.rst

@@ -3,6 +3,15 @@ Change Log
 
 [upcoming release] - 2024-..-..
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+- [ADDED] Implementation of Allocation Factor WLS (AF-WLS) for non observable distribution grids
+- [FIXED] Deletion of multiple measurements at the same bus or branch
+- [FIXED] Creation of zero injection measurements in WLS estimator
+- [FIXED] Divergence of WLS estimator with flat start for highly loaded grids
+- [ADDED] Computation of matrix conditioning and warning in case of ill-conditioning
+- [FIXED] Issue with initialization of WLS estimator
+- [FIXED] Handling of current magnitude measurements in WLS estimator
+- [ADDED] Created estimation results for shunt elements
+- [FIXED] Fixed issue with power injection results in WLS estimator
 - [FIXED] cim2pp add missing description to dcline
 - [ADDED] pandas series accessor for geo column
 - [FIXED] Increasing geojson precision as the default precision might cause problems with pandahub