"-version" option vs. "version" command

This is a little thing, but it strikes me as odd that `zync` uses a "command" to get the version:

```
$ zync version
d87d49b
```

Whereas the other Zed tools all use a `-version` option.

```
$ zed -version
Version: v1.1.0-44-g28029f06

$ zq -version
Version: v1.1.0-44-g28029f06
```