github: remove ubuntu-18.04

Unfortunately, it's deprecated and not working properly:
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/

Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index b3b0a7a6503f75deba0869c47410cd4b925d07df..57bd574fed421c5dbf41c19956b2df8cfa20fb04 100644 (file)
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -16,7 +16,6 @@ jobs:
           - gcc
           - clang
         os:
-          - ubuntu-18.04
           - ubuntu-20.04
           - ubuntu-22.04
     runs-on: ${{ matrix.os }}