Add back an ubuntu workflow with C++20

.github/workflows/ubuntu.yml

@@ -0,0 +1,52 @@
+
+name: ubuntu
+
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        LCG: ["dev3/x86_64-ubuntu2404-gcc13-opt",
+              "dev4/x86_64-ubuntu2404-gcc13-opt"]
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cvmfs-contrib/github-action-cvmfs@v4
+    - uses: aidasoft/run-lcg-view@v4
+      with:
+        release-platform: ${{ matrix.LCG }}
+        run: |
+          echo "::group::Run CMake"
+          export JULIA_DEPOT_PATH="$(mktemp -d -p /tmp -t julia_depot_XXXXX):"
+          mkdir build install
+          cd build
+          cmake -DENABLE_SIO=ON \
+            -DENABLE_JULIA=ON \
+            -DENABLE_DATASOURCE=ON \
+            -DCMAKE_INSTALL_PREFIX=../install \
+            -DCMAKE_CXX_STANDARD=20 \
+            -DCMAKE_CXX_FLAGS=" -fdiagnostics-color=always -Werror -Wno-error=deprecated-declarations " \
+            -DUSE_EXTERNAL_CATCH2=OFF \
+            -DPODIO_SET_RPATH=ON \
+            -DENABLE_RNTUPLE=ON \
+            -G Ninja ..
+          echo "::endgroup::"
+          echo "::group::Build"
+          ninja -k0
+          echo "::endgroup"
+          echo "::group::Julia StaticArrays Package Install"
+          julia -e 'import Pkg; Pkg.add("StaticArrays")'
+          echo "::endgroup"
+          echo "::group::Run tests"
+          ctest --output-on-failure
+          echo "::endgroup::"
+          echo "::group::Install"
+          ninja install
+          echo "::endgroup::"