make `--version` to report the binary version again

[dopstar]

Fixes https://github.com/librespeed/speedtest-cli/issues/57

[homotechsual]

Would be great to see this merged and ideally for the binary to actually use the Version property on Windows and others where supported.

C:\RMM\Bin> (Get-Command 'C:\RMM\Bin\librespeed-cli.exe').Version

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