⚗️ try to install GCC 11

.github/workflows/ubuntu.yml

@@ -68,16 +68,19 @@ jobs:
 
     steps:
       - uses: actions/checkout@v1
-      - name: install_gcc
+      - name: install_ninja
         run: |
           sudo apt update
-          sudo apt install gcc-10 g++-10 ninja-build
+          sudo apt install ninja-build
+        shell: bash
+      - name: install_gcc
+        run: |
+          sudo add-apt-repository ppa:ubuntu-toolchain-r/test
+          sudo apt update
+          sudo apt install gcc-11
         shell: bash
       - name: cmake
         run: cmake -S . -B build -DJSON_CI=On
-        env:
-          CC:   gcc-10
-          CXX:  g++-10
       - name: build
         run: cmake --build build --target ci_test_gcc --parallel 10
 
@@ -99,8 +102,5 @@ jobs:
         shell: bash
       - name: cmake
         run: cmake -S . -B build -DJSON_CI=On
-        env:
-          CC:   clang-11
-          CXX:  clang++-11
       - name: build
         run: cmake --build build --target ci_test_clang --parallel 10