tree 4a1dd596010ca56723907402d8f414d30aeb9704
parent ce74ca2b1c968f897150bdc55daa9e3c12a3fefc
author Sam Clegg <sbc@chromium.org> 1716918396 -0700
committer Sam Clegg <sbc@chromium.org> 1716918851 -0700

[TESTING] Upgrade CI to Ubuntu20.04 LTS (Focal)

On one hand Ubuntu18's free LTS cycle is ended, and on the other hand Ubuntu18 does not support nodejs greater than v18.
1. update the Linux Docker image to buildpack-deps:focal
2. some compatibility changes
3. use the new recommended way to install Docker ([see here](https://docs.docker.com/engine/install/ubuntu/))

See https://github.com/emscripten-core/emsdk/issues/1173