[C++] Add clang-17 to GHA

Signed-off-by: Stefan Marr <git@stefan-marr.de>

.github/workflows/ci.yml

@@ -40,6 +40,14 @@ jobs:
           ~/.asdf/bin/asdf plugin add awfy https://github.com/smarr/asdf-awfy.git
         if: matrix.id == 'squeak' || matrix.id == 'pharo'
 
+      - name: Install Clang 17
+        run: |
+          wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+          sudo add-apt-repository "deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-17 main"
+          sudo apt-get update
+          sudo apt-get install -y clang-17 clang-format-17 clang-tidy-17
+        if: matrix.id == 'cpp'
+
       - name: Install Crystal
         if: matrix.id == 'crystal'
         uses: oprypin/install-crystal@v1