ci: remove ubuntu-20.04 runner builds on GHA

The Ubuntu 20.04 image on GitHub actions will be unavailable by
2025-04-01, and that is no April Fool's joke. See
<actions/runner-images#11101> for more
information on the deprecation and removal. (Looks like the date
was moved two weeks back to 2025-04-15, but it's time to get rid
of those builds anyway.)

Therefore, the GCC 8 build on Ubuntu 20.04 is removed, and a new
GCC 13 build on Ubuntu 24.04 is added instead. Furthermore, the
Clang 7, 8, 9 and 10 builds on Ubuntu 20.04 are removed, and new
builds for Clang 12 on Ubuntu 22.04 as well as Clang 17, 18 and
19 on Ubuntu 24.04 are added.

Author: striezel

.github/workflows/clang.yml

@@ -8,20 +8,20 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - version: 7
-            os: ubuntu-20.04
-          - version: 8
-            os: ubuntu-20.04
-          - version: 9
-            os: ubuntu-20.04
-          - version: 10
-            os: ubuntu-20.04
           - version: 11
             os: ubuntu-22.04
+          - version: 12
+            os: ubuntu-22.04
           - version: 14
             os: ubuntu-22.04
           - version: 16
             os: ubuntu-24.04
+          - version: 17
+            os: ubuntu-24.04
+          - version: 18
+            os: ubuntu-24.04
+          - version: 19
+            os: ubuntu-24.04
     runs-on: ${{ matrix.os }}
     steps:
       # Checks-out the repository under $GITHUB_WORKSPACE.
@@ -32,10 +32,6 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install -y catch cmake clang-${{ matrix.version }} libxml2-dev pkg-config zlib1g-dev
-      - name: Install LLVM C++ Standard Library
-        run: |
-          sudo apt-get install -y libc++-${{ matrix.version }}-dev
-        if: matrix.version == 8
       - name: Build with Clang ${{ matrix.version }}
         run: |
           export CXX=clang++-${{ matrix.version }}

.github/workflows/gcc.yml

@@ -8,8 +8,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - version: 8
-            os: ubuntu-20.04
           - version: 9
             os: ubuntu-22.04
           - version: 10
@@ -18,6 +16,8 @@ jobs:
             os: ubuntu-22.04
           - version: 12
             os: ubuntu-24.04
+          - version: 13
+            os: ubuntu-24.04
           - version: 14
             os: ubuntu-24.04
     runs-on: ${{ matrix.os }}