[GRASS-git] [OSGeo/grass] bb9ac5: CI: Remove Ubuntu 18.04 check

[Vaclav Petras]

  Branch: refs/heads/wenzeslaus-patch-1
  Home:   https://github.com/OSGeo/grass
  Commit: bb9ac5e11a89a052acfa7dd518cf145053438400
      https://github.com/OSGeo/grass/commit/bb9ac5e11a89a052acfa7dd518cf145053438400
  Author: Vaclav Petras <wenzeslaus at gmail.com>
  Date:   2022-04-26 (Tue, 26 Apr 2022)

  Changed paths:
    M .github/workflows/ubuntu.yml

  Log Message:
  -----------
  CI: Remove Ubuntu 18.04 check

We don't support Ubuntu 18.04 for 8.0 anymore.