Fix: Improve build command for windows compatibility

HI,
I encountered an issue when following the installation stpes on windows 11. The the resulting file is named dockerlings without the .exe. Consequently, powershell does not recognize it as an executable.

Would you consider updating the build command to use go env GOEXE?
``` bash
go build -o bin/dockerlings$(go env GOEXE) ./cmd/dockerlings
```