STYLE: misleading fall-through value (#10)

- unused fall-through value, but should default to "Always"

src/petsc4Foam/utils/petscCacheManager.H

@@ -296,8 +296,8 @@ private:
             }
         }
 
-        // Default: Never
-        return false;
+        // Default: Always update
+        return true;
     }
 };