Adopt semantic versioning and add -version flag

[lolbinarycat]

There is currently one release listed (1.0.0) and it is from ~6 years ago. adding a -version flag would help with development, as you could actually tell what version of the binary you were running.

[lolbinarycat]

This would also probably require a separate dev branch, so not every commit is a new minor/patch version.

[lolbinarycat]

I am also working on a pr for a larger buildinfo feature.