Migrate away from deprecated `heroku/buildpacks:20` CNB builder image

[edmorley]

Hi 👋

This project uses Heroku's heroku/buildpacks:20 CNB builder image:

architect-cli/src/common/plugins/buildpack-plugin.ts

Line 8 in a31e056

private readonly builder = 'heroku/buildpacks:20';

We have deprecated this builder image as of heroku/cnb-builder-images#429.

Please migrate to heroku/builder:22 or heroku/builder:20, to continue to receive security updates, and to avoid disruption when the build time deprecation warning is upgraded to an error in the future.

More information on the difference between the various builder images can be seen here:
https://github.com/heroku/cnb-builder-images#heroku-cnb-builder-images

The docs here will also need updating:
https://github.com/architect-team/documentation/blob/e7cac6926ead5058214bbef8c1d00b8b728c9267/components/services.mdx#L80

[edmorley]

Gentle nudge that builds using these images will start erroring in the future, plus the underlying images themselves will stop receiving security updates.

[edmorley]

@ryan-cahill @TylerAldrich ^

[edmorley]

Gentle nudge that builds using these images will start erroring in the future, plus the underlying images themselves will stop receiving security updates.

This will be happening within the next couple of weeks in heroku/cnb-builder-images#474. We'll be adding an env var override for the errors, but I strongly recommend you switch from heroku/buildpacks:20 to heroku/builder:* as soon as possible.

[edmorley]

Please migrate to heroku/builder:22 or heroku/builder:20, to continue to receive security updates, and to avoid disruption when the build time deprecation warning is upgraded to an error in the future.

The deprecation warnings were upgraded to errors this morning:
heroku/cnb-builder-images#478

[edmorley]

As of yesterday, the legacy heroku/buildpacks:20 and heroku/builder-classic:22 builder images are no longer updated, and so won't receive security updates, fixes or support for new language runtime version releases. Please switch to using the heroku/builder:* images instead:
https://github.com/heroku/cnb-builder-images#available-images