Add clang 17 to list of GitHub Actions (thanks to @striezel)

See nonstd-lite-project issue 75, nonstd-lite/nonstd-lite#75 (comment)

Author: martinmoene

.github/workflows/ci.yml

@@ -52,6 +52,8 @@ jobs:
             os: 'ubuntu-22.04'
           - version: 12
             os: 'ubuntu-22.04'
+          - version: 17
+            os: 'ubuntu-24.04'
 
     runs-on: ${{ matrix.os }}