Update CI ubuntu image and clang version

Update the Clang version used when running tests in CI. To make that
happen, bump the Ubuntu base image in use as well. We need something
more recent than Clang 14 to have proper enum64 support [0].

[0] #1035

Signed-off-by: Daniel Müller <deso@posteo.net>

.github/workflows/test.yml

@@ -12,7 +12,7 @@ on:
 jobs:
   test:
     name: Test [${{ matrix.rust }}, ${{ matrix.profile }}]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     strategy:
       fail-fast: false
       matrix:
@@ -52,9 +52,9 @@ jobs:
         components: rustfmt
     - name: Install deps
       run: |
-        sudo apt-get install -y clang-14 libelf-dev zlib1g-dev linux-headers-$(uname -r)
+        sudo apt-get install -y clang-18 libelf-dev zlib1g-dev linux-headers-$(uname -r)
         sudo ln -s /usr/include/asm-generic /usr/include/asm
-        sudo rm -f /bin/clang && sudo ln -s /usr/bin/clang-14 /bin/clang
+        sudo rm -f /bin/clang && sudo ln -s /usr/bin/clang-18 /bin/clang
     - uses: Swatinem/rust-cache@v2
     - name: Build
       run: cargo build --profile=${{ matrix.profile }} --locked --verbose --workspace --exclude runqslower