Update CHANGELOG

CHANGELOG.md

@@ -55,6 +55,7 @@ v4.4.0
 - Allow equi-spaced output for 1D and 2DH1D fields (!613)
 - Update quality metric to include scaled Jacobian output (!695)
 - Allow multiple XML files to be specified in InterpField module (!705)
+- Fix issues with isocontour module (!719)
 
 **NekMesh:**
 - Modify curve module to allow for spline input (!628)