build: Fix tests not running
common/flags: Update to latest upstream
ci: Update to zig 0.11
build: Fix if build_root.path is null
Update to zig 0.11
README: Add a link to zelbar-river
data: Remove pointer arg in render()

This was not needed, remove the need for @ptrCast().

Lot of things changed (yes it should have been made in multiple commit):
  * Removed scale for now, it was really buggy
  * Bar: Move everything that was related to wayland to Backend.zig.
  * Backend: Move the creation, configuration and rendering of the
    surface in Surface.send_frame().
  * Add some doc comments
  * Cleanup
Backend: Cleanup global interfaces versions
Backend: Remove Seat name

No need to allocate memory for something we don't use.
README: Add more buildings requirements
Render only in response to frame callbacks
Backend: Rewrite BufferPool
deps: Update zig-wayland
common: Update flags to latest upstream
ci: Update Wayland to 1.21
Update to zig 0.10
Backend: Use null data instead of undefined
Implement pointers events and  action on click

New format:
  Send <action> to STDOUT