Fix older versions of react native changelog URLs

[ItaloFalzoni]

Summary

The previous React Native changelog files have been changed to another file. For example, the version 0.68 of react native has been changed to this link: https://github.com/facebook/react-native/blob/main/CHANGELOG-pre-070.md#v0680, before we were use this link: https://github.com/facebook/react-native/blob/main/CHANGELOG.md#v068 and it was not working very well.

Basically I added an extra function that checks versions prior to 0.70 and invokes a new function that is responsible for assembling the changelog URLs.

Test Plan

yarn start

What are the steps to reproduce?

You can see it live and check the link on the "Useful content for upgrading" section

Checklist

• I tested this thoroughly
• I added the documentation in README.md (if needed)

[JVGS1111]

Can you guys check this?

[kelset]

@ItaloFalzoni can you verify that TS checks green locally? on CI it errors with Cannot set property mark of #<Object> which has only a getter (plus there's also an eslint error)

[ItaloFalzoni]

@kelset

Sorry. I coded on Github Codespace and I didn't see how the TS check works. As soon as possible I will look again to make the review easier. Thanks.