Do not build with Ubuntu 18, use 24 (#1613)

Re-delete file that was undeleted accidentally

.github/workflows/linux.yml

@@ -19,9 +19,9 @@ jobs:
       matrix:
         os:
           - amazonlinux:2023
-          - ubuntu:18.04
           - ubuntu:20.04
           - ubuntu:22.04
+          - ubuntu:24.04
     runs-on: ubuntu-latest
     container:
       image: ${{ matrix.os }}

.github/workflows/ubuntu_tests.yml

@@ -1,36 +0,0 @@
-name: Ubuntu
-
-on:
-  push:
-  pull_request:
-    types: [ opened, reopened, synchronize ]
-
-# make GHA actions use node16 to use ancient container images
-# See https://github.blog/changelog/2024-03-07-github-actions-all-actions-will-run-on-node20-instead-of-node16-by-default/
-# Unclear how long this will work though
-env:
-  ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
-
-jobs:
-  builds:
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [ 'ubuntu:18.04', 'ubuntu:20.04', 'ubuntu:22.04' ]
-    runs-on: ubuntu-latest
-    container: ${{ matrix.os }}
-    steps:
-    - uses: actions/checkout@v3
-    - name: Install dependencies
-      # Set env variable or otherwise tzdata package requires interaction
-      env:
-        DEBIAN_FRONTEND: noninteractive
-      uses: ./.github/workflows/actions/ubuntu-build-deps
-    - name: configure
-      run: ./configure
-    - name: make
-      run: make
-    - name: make check
-      run: make check
-    - name: apps tests
-      run: cd examples && ./run_tests.sh && ./run_tests_conf.sh && ./run_tests_prom.sh