Port #1504 (dash separators in version strings) to 2.x

[zorgiepoo]

On second thought I realized we can support this without doing any date comparison because the code just picks the first item if two are equal.

Checklist:

• My change is being tested and reviewed against the Sparkle 2.x branch. New changes must be developed on the 2.x development branch first.
• My change is being backported to master branch (Sparkle 1.x). Please create a separate pull request for 1.x, should it be backported. Note 1.x is feature frozen and is only taking bug fixes, localization updates, and critical OS adoption enhancements.
• I have reviewed and commented my code, particularly in hard-to-understand areas.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• My change is or requires a documentation or localization update

Testing

I tested and verified my change by using one or multiple of these methods:

• Sparkle Test App
• Unit Tests
• My own app
• Other (please specify)

Tested when two items are equal in test app feed, first one is picked.
Ran unit tests.

macOS version tested: 11.3 (20E232)

[zorgiepoo]

The thing I don't get is and maybe part of why I was so against this change earlier, even if this is supported, Sparkle is still not going to pick an equal version if the user has an equal version installed.

Oh well, there's no harm in ignoring -* anyway.