Default config uses dmenu_path, wich is part of dmenu, but not listed in optional deps

Description:

Sway uses dmenu_path in its default config. At some point, the menu provider was switched from dmenu to wmenu, but since dmenu_path is provided by dmenu and not wmenu, sway should still optionally depend on dmenu.

Additional info:

• package version(s): 1:1.9-1
• config and/or log files: default config
• link to upstream bug report, if any: N/A, packaging issue

Steps to reproduce:

1. Install sway on a fresh install of Arch Linux
2. Install the wmenu optional dependency
3. Launch sway
4. Press Super+d
5. Notice that wmenu does not show any programs, since dmenu_path is not installed
6. Notice that the sway log contains 'sh: line 1: dmenu_path: command not found'

Suggested Fix:

Add dmenu to optional dependencies