Log Message:
cwm: Update to 6.7

2020-05-22: Seventh public release 6.7 of portable cwm.

Changes made between OpenBSD 6.6 and 6.7
* Allowed cwm(1) configuration of window size based on percentage of
  the master window during horizontal and vertical tiling actions.
* Allowed use of window-htile and window-vtile with the "empty" group
  clients in cwm(1).