fix: use node actions for v16

[basscl]

When I tried to push to squarecandy-luna github actions failed with message:

build (16.x)
Node.js 12 actions are deprecated. Please update the following actions to use Node.js 16: actions/checkout@v2, actions/setup-node@v1. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/.

This seems to fix that issue.

[petertwise]

I merged this and this is a good fix for now.
We should probably start supporting Composer v2 soon ... maybe the updates we have made recently actually get us there.