Update CHANGELOG.md to include information about the addition of the diagCorr function

CHANGELOG.md

@@ -33,6 +33,9 @@
 \* Fix error in `virtMicGeo()` not returning the z coordinates of the virtual microphones in the mesh. This fix **breaks backward compatibility**.\
 \* Change name of `virtMicGeo()` to `vMicGeo()`. This **breaks** backward compatibility.
 
+**Utilities - Generic**\
+\+ Added the function `diagCorr()` to calculate the correlation coefficient of a matrix to a diagonal matrix. In practice this provides a metric to measure the "diagonality" of a matrix. 
+
 **Virtual Sensing - Remote Microphone Technique**\
 \* Parallelise the for-loops in `obsFiltEst()`. While execution may be slower for a small number of sources and receiver positions, the overall execution time will not increase significantly due to the functions' generally fast performance.\
 \* Parallelise on of the for-loops in `obsFiltTD()`. While execution may be slower for a small number of sources and receiver positions, the overall execution time will not increase significantly due to the functions' generally fast performance.\