Add flag to switch to a semantic version ordering

[cruelsmith]

Is your feature request related to a problem? Please describe.
Projects that maintaining multiple major / minor versions at the same time end up with semantic unordered changelogs with not working diffs like v4.0.0 to v3.5.10 because v3.5.10 has been released after v4.0.0.

Describe the solution you'd like
Flag to switch to a semantic version ordering.

Current ordering based on tag date: v3.5.9, v4.0.0, v3.5.10, v4.1.0
Wanted ordering based on semantic Versioning: v3.5.9, v3.5.10, v4.0.0, v4.1.0

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
https://github.com/github-changelog-generator/github-changelog-generator/blob/master/lib/github_changelog_generator/generator/generator_tags.rb#L12

[yykamei]

OK, something like --tag-order ORDER, of which the ORDER is either of date or version, is good? I agree with you 👍