CI builds on Ubuntu less than 20.04 are failing

[esabol]

The ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION=true workaround has stopped working.

Might need to finally drop all of our CI builds for gcc/g++ 4.8.x through 8.x. :(

I'm investigating the following workarounds:

• https://github.com/barlesh/workaround-gh-co-and-artifact-on-old-os/blob/main/.github/workflows/ci.yml

• nodesource/distributions#1392 (comment)

Not sure how much effort I want to put into this. I think the first workaround sounds promising.

[esabol]

Found a new workaround for building/testing on older Ubuntu versions that should fit our needs:

actions/checkout#1590 (comment)

I just need to find some time to implement it into our ci.yml file.

I recently discovered https://github.com/nektos/act/, which allows you to run GitHub Actions workflows locally. If I can get that working, that would make developing/testing GitHub Actions workflows much easier.