Add semantic versioning tagging



Deploy Plan
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Does Infrastructure need to know anything special about this deploy? If so, keep this section and fill it in. **Otherwise, delete it.**

Rollback Plan
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**If this pull request requires anything more complex (e.g., rolling back a migration), you MUST update this section. Otherwise, delete this note.**

To roll back this change, revert the merge with `git revert -m 1 MERGE_SHA` and perform another deploy.

URLs
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* [Jira issue MOBILE-635](https://sportngin.atlassian.net/browse/MOBILE-635)

QA Plan
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Provide a detailed QA plan, or other developers will retain the right to mock you mercilessly.

I feel like this reads a little better:

```ruby
def tag_semver
  current_version = get_current_version
  ask_user_version  unless @major || @minor || @patch
  new_version = upgrade_version current_version
  new_version.to_s
end
```

That said, you could argue that the conditional could live in it's own method (something like `patch_change_set?`), or you could move the conditional to the `ask_user_version` method.  It is a pedantic change regardless.