documentation on how to upgrade Gatsby apps

[derekeder]

Documentation request

For green-jobs I wanted to use this new plugin, but it was only compatible with gatsby@^3.0.0. We're on gatsby@2.19.45 so it required an upgrade.

I looked up the documentation on migrating from gatsby 2 to 3 and it gave a long list of instructions that I wasn't really sure about. I tried upgrading gatsby and gatsby-plugin-sharp running docker-compose run --rm app upgrade gatsby@latest --save, but it looks like I would have needed to upgrade every incompatible dependency manually. So I stopped there, reverted, and ditched the plugin.

It would be helpful to have documentation on how we'd like to upgrade gatsby apps in our Docker context

[smcalilly]

related to #273.

[smcalilly]

for #273, here is some stuff i did based on the migration guide derek shared:

• docker-compose run --rm app upgrade-interactive --latest to go through the old dependencies and upgrade them in one swoop.
• that didn't catch everything so i deleted the yarn.lock file and then docker-compose run --rm app install. i did this several times til i whittled away all of the dependency warnings i saw in the console.
• combed through the gatsby-config.js file and made sure all of those plugins had the correct config that matched the latest versions

also had to follow this migration guide:

• https://www.gatsbyjs.com/docs/reference/release-notes/image-migration-guide/

[smcalilly]

goodbye gatsby