CI: use Ubuntu 24.04 for gcc 13 builds

We don't need the setup-gcc script, it's already using
gcc 13.

.github/workflows/linux.yaml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        cxx: ['7', '13']
+        cxx: ['7']
     env:
       CMAKE_OPTIONS: -DDEV_MODE=ON -DBUILD_TESTING=ON -G Ninja
     steps:
@@ -33,6 +33,29 @@ jobs:
 
       - name: Run tests
         run: ctest --test-dir _build
+
+  Linux-GCC-latest:
+    runs-on: ubuntu-latest
+    env:
+      CMAKE_OPTIONS: -DDEV_MODE=ON -DBUILD_TESTING=ON -G Ninja
+    steps:
+      - uses: lukka/get-cmake@latest
+
+      - name: Get pushed code
+        uses: actions/checkout@v4
+
+      - name: Configure
+        run: cmake -S . -B _build ${{ env.CMAKE_OPTIONS }} -DCMAKE_INSTALL_PREFIX:STRING=${GITHUB_WORKSPACE}/_built
+
+      - name: Build
+        run: cmake --build _build --parallel
+
+      - name: Test installation
+        run: cmake --install _build --prefix ${GITHUB_WORKSPACE}/_built
+
+      - name: Run tests
+        run: ctest --test-dir _build
+
   Linux-Clang:
     runs-on: ubuntu-20.04
     strategy:
@@ -64,6 +87,7 @@ jobs:
 
       - name: Run tests
         run: ctest --test-dir _build
+
   Alpine:
     runs-on: ubuntu-latest
     strategy: