`eww` always installs v0.5.0

Pacman thinks it's v0.6.0...
```
$ pacman -Qs eww
local/eww 0.6.0-1
    Standalone widget system made in Rust
```

... But the real version is v0.5.0
```
$ eww -V
eww 0.5.0 d87c2fdbfdc012e76d229e4e9ea3325bc0f23e89
```