build-idris-package: Use patchPhase for consistency

pkgs/development/idris-modules/build-idris-package.nix

@@ -36,9 +36,10 @@ stdenv.mkDerivation ({
   # Some packages use the style
   # opts = -i ../../path/to/package
   # rather than the declarative pkgs attribute so we have to rewrite the path.
-  postPatch = ''
+  patchPhase = ''
     runHook prePatch
     sed -i ${ipkgName}.ipkg -e "/^opts/ s|-i \\.\\./|-i ${idris-with-packages}/libs/|g"
+    runHook postPatch
   '';
 
   buildPhase = ''