Fix sorting to work properly with multi-digit version numbers

[perlun]

Right now, it sorts like this:

## 1.4.0
[Full Changelog](https://github.com/ecraft/blurf/compare/1.3.0...1.4.0)

* 132d945 Merge pull request #83 from ecraft/fix/extract-workerd-method
* c4ffa5e Extract method.

## 1.3.0
[Full Changelog](https://github.com/ecraft/blurf/compare/1.23.0...1.3.0)


## 1.23.0
[Full Changelog](https://github.com/ecraft/blurf/compare/1.22.0...1.23.0)

* 3da262e Attempt to fix 'bundle install' issue on Travis. (#131)
* 727c94b Added foreman, README update
* 1dac76c Make it work in PROD
* 150fb6d Fixed typo

...which is obviously wrong. 1.23.0 is ascii-wise lower than 1.3.0, but not numerically wise.

[perlun]

I looked a bit into this. It's a bit nontrivial since we will need to retain both the potentially v1.4.x and 1.4.y strings (one being a string, the other being a Version instance). That said, it can definitely be fixed, it's just a bit more work.

[perlun]

This is an annoying bug; it's laughable really. We should fix it.

Workaround for the time being:

$ changelog-rs . 2014.0.12 2014.0.13

[perlun]

I am being bothered by this again. If someone wants to fix it, I'll be very happy to help you with some details on how it can be sorted out.