Remove ubuntu-18.04
Remove ubuntu-18.04

This runner is deprecated https://github.blog/changelog/2022-08-09-github-actions-the-ubuntu-18-04-actions-runner-image-is-being-deprecated-and-will-be-removed-by-12-1-22/
meziantou/Meziantou.Framework,meziantou/Meziantou.Framework,meziantou/Meziantou.Framework,meziantou/Meziantou.Framework