Add react-native upgrade-windows command

[rozele]

We're going to need something to re-run the yeoman generator (like react-native upgrade).

[achipa]

Any progress/plan on this? The recent change in how Yoga is referenced was a good example why this can come handy (as opposed to manually mucking with templates and figuring out what/how has changed in csproj/sln templates)

[rozele]

@achipa Thanks for pinging on this. I think the right solution is to build the right, stable project configuration hooks into react-native-windows so we don't have to deal with breaking changes. One such attempt was recently added in the 0.55 RC:
cdde4d7

The problem comes along with what projects need to be added to the .sln file, as this is not something you can "modularize". The "right" thing to do is to publish a compiled version of react-native-windows on NuGet so you don't need to include the projects in the solution, but realistically we're still a ways from that. There are many arguments to be made for building from source (many enterprises require it, we can guarantee we're using the same Yoga implementation across platforms, native debugging is easier, etc.)

[rozele]

So, I think I've just convinced myself we need to bump the priority on this so we can easily support building from source :-)

[rozele]

Not sure if this is a dupe or just related to #1358

[achipa]

Related (two different implementation points for the same issue), in the sense that it's a separate project for upgrading the templates via git, whereas this issue describes it as part of react-native-windows.

I can think of arguments for both, so can't really say I have a preference (as long as there is a way to track these upgrades in at least a semi-automated fashion).

[ghost]

We are not investing in new features or lower priority bug fixes on vCurrent. The bulk of investment is now in vNext as we prepare to make that the default choice. If this issue is still relevant on the vNext implementation please open a vNext issue. If this issue is of significant severity for a vCurrent app and vNext is not an option, re-open with justification.