Use an idempotent, predictable output filename to prevent firewall warnings

[Southclaws]

It seems this is unmaintained but figured I'd raise this anyway.

A reason I usually go build -o app.exe ; ./app.exe is to keep security software from treating each compilation as a new binary (because it uses a temporary directory). Otherwise, if the application wants access to certain resources such as network sockets, webcams, sound, etc. then you must hit "allow access" for every compilation.

I went to try this app, and it seems it also uses a different output name for every compilation. Resulting in this:

It also doesn't seem to clean up these temporary binaries, which has resulted in my %userprofile%/go/bin directory filling up with executables named watcher-.-(random ID).