⚗️ try official Clang containers

.github/workflows/ubuntu.yml

@@ -105,6 +105,21 @@ jobs:
       - name: Build
         run: cmake --build build --target ci_test_compiler_default
 
+  ci_test_compilers_clang:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        compiler: ['3.5', '3.6', '3.7', '3.8', '3.9', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14']
+    container: silkeh/clang:${{ matrix.compiler }}
+    steps:
+      - uses: actions/checkout@v3
+      - name: Get latest CMake and ninja
+        uses: lukka/get-cmake@latest
+      - name: Run CMake
+        run: cmake -S . -B build -DJSON_CI=On
+      - name: Build
+        run: cmake --build build --target ci_test_compiler_default
+
 #  ci_test_compilers:
 #    runs-on: ubuntu-latest
 #    container: ghcr.io/nlohmann/json-ci:v2.4.0