remove unsupported targets from readme
remove unsupported targets from readme

See #438

Dimenus/zig,Dimenus/zig,raulgrell/zig,raulgrell/zig,andrewrk/zig,raulgrell/zig,raulgrell/zig,raulgrell/zig,zig-lang/zig,Dimenus/zig,zig-lang/zig,andrewrk/zig,zig-lang/zig