bug: fix bug in _GridInterpolator class (#79)

Author: vegard-solum-4ss

src/waveresponse/_core.py

@@ -1076,8 +1076,8 @@ def reshape(
         self._check_dirs(dirs_new)
 
         interp_fun = _GridInterpolator(
-            freq_new,
-            dirs_new,
+            self._freq,
+            self._dirs,
             self._vals,
             complex_convert=complex_convert,
             method="linear",