0.60 and tooling

[turnrye]

This PR adds some improvements to the changelog generator, plus the 0.60 changelog that was dogfooded using the tool.

One important note about this: something about the 0.59 -> 0.60 branch comparison on Github has broken their API (unrelated to my changes). It is not returning all of the results. This MR has been WIP for a long, long time, and I've nudged many community members to check this for any important missing changes. I anticipate however that not everyone got that message, and therefore we will have various corrections to the changelog after this ships. I'm ready to make those fixes, and moving into the future release I plan to more directly tackle the API issue that we encountered.

[kelset]

hey Ryan, I was looking through the changelog and I couldn't find a reference to this commit react/react-native@a2285b1

Which is the one bringing "feature parity" to the inline views, that were possible in iOS from a long time (via react/react-native@486dbe4).

While looking into this, I also found this other commit react/react-native@a2a03bc which gives a few important insights:

Note that some examples are only supported on iOS because they rely on the inline view being able to size to content. Android's implementation requires that a width and height be specified on the inline view.

(but this is something that probably should live in the docs)

And also a whole list of limitations.
So probably worth writing something like "brings feature parity but be aware that it has some limitations", and maybe the link to the commit?

(more details on the whole thing here react/react-native#25197 (comment))

[kelset]

We should probably mention something around the use_frameworks! issue -> react/react-native#25349

maybe we could have a line at the start saying something like "We are aware that rhe changes in 0.60.0 to integrate CocoaPods by default are causing build failures if your Podfile includes use_frameworks!." and tell them to check the issue for details of workarounds and mention that there is a PR in the works to fix it but that it will likely only land for 61