added changelog entry

CHANGELOG.md

@@ -150,6 +150,7 @@ v5.0.0
 - Made Sutherland's law non-dimensional (!972)
 - Modified pressure outlet BCs to allow for the reference static pressure to be
   set from the VALUE fields (!981)
+- hp scaling for Laplacian AV (!1013)
 
 **AcousticSolver:**
 - Added two new boundary conditions to the APE system: RiemannInvariantBC