Add support for upgrading SharePoint Framework 1.0.0

[baywet]

Everything is in the title.
I was looking to upgrade https://github.com/SharePoint/sp-dev-fx-webparts/tree/master/samples/knockout-sp-pnp-js to latest + @pnp/sp as well as https://docs.microsoft.com/en-us/sharepoint/dev/spfx/web-parts/guidance/use-sp-pnp-js-with-spfx-web-parts

[waldekmastykarz]

Originally, we were planning to stop at v1.1.0 which is the version currently recommended for on-prem but we could go even further to v1.0.0. Want to take a stab at it?

[baywet]

@waldekmastykarz thanks for the follow up!
I think it'd be important to support it as quite a few samples are running 1.0.0, as well as because people might have started real life projects back then that they want to pick up.
For the preview versions, my opinion is I think we can leave it for a couple of reasons:

• Only a few "early adopters" (MVPs, partners, …) used those versions
• Nobody is supposed to have done real production projects with those versions
  What do you think?
  I'm happy to help: do you have guidance to start implementation? Recommendations? Also in terms of figuring the changes between SPFX versions, I couldn't find a changelog for 1.0.0 => 1.0.1, 1.0.1 => 1.0.2, 1.0.2 => 1.1.0 besides AC's blog.
  How do you usually get around that? do you scaffold to projects (one for each version) and compare?

[waldekmastykarz]

Fully agreed that we should skip preview versions. Regarding the guidance on implementing SPFx project upgrades: unfortunately I didn't get to document it yet, but @VelinGeorgiev and myself implemented a few things so I'd say: have a look at the other versions that are already implemented and don't hesitate to reach out if something isn't clear. Sorry, we don't have docs for it.
To discover what's changed between the versions, I always run a diff between all project types created in each version. Changelogs don't cover the changes in sufficient detail unfortunately. To create the different project types I use the following script https://gist.github.com/waldekmastykarz/92fea35dfcccaae6b978cb6b100a6f23 although it might need adjustment for the older versions.

[baywet]

alright, thanks for the details! You can assign it to me, I'll try to tackle it next week.