Fix and modernize clang-tidy CI config

Author: joto

.github/workflows/clang-tidy.yml

@@ -13,16 +13,16 @@ jobs:
           - image: "debian:trixie"
             clang: 19
           - image: "debian:testing"
-            clang: 21
-#          - image: "debian:experimental"
-#            clang: 21
+            clang: 22
+          - image: "debian:experimental"
+            clang: 23
     container:
       image: ${{ matrix.image }}
       env:
         BUILD_TYPE: Dev
         CC: clang-${{ matrix.clang }}
         CXX: clang++-${{ matrix.clang }}
-        CPP_VERSION: c++17
+        CPP_VERSION: 17
         APT_LISTCHANGES_FRONTEND: none
         DEBIAN_FRONTEND: noninteractive
     steps: