Add ccache-swig hash fix to RELEASENOTES

Author: wsfulton

RELEASENOTES

@@ -9,6 +9,7 @@ published on the SWIG web site at https://swig.org/release.html.
 
 SWIG-4.1.1 summary:
 - Couple of stability fixes.
+- Stability fix in ccache-swig when calculating hashes of inputs.
 - Some template handling improvements.
 - R - minor fixes plus deprecation for rtypecheck typemaps being optional.