CI: Manually add apt repo for llvm 20 to all relevant jobs

Author: https://github.com/ADKaster
Commit: 09ed4bd265
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4736

.github/actions/setup/action.yml

@@ -33,8 +33,8 @@ runs:
 
         sudo add-apt-repository ppa:ubuntu-toolchain-r/test
 
-        wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-        sudo add-apt-repository 'deb http://apt.llvm.org/noble/ llvm-toolchain-noble-20 main'
+        wget -O /usr/share/keyrings/llvm-snapshot.gpg.key https://apt.llvm.org/llvm-snapshot.gpg.key
+        echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.key] http://apt.llvm.org/noble/ llvm-toolchain-noble-20 main" | sudo tee -a /etc/apt/sources.list.d/llvm.list
 
         sudo apt-get update -y
         sudo apt-get install -y autoconf autoconf-archive automake build-essential ccache cmake curl fonts-liberation2 \

.github/workflows/js-benchmarks.yml

@@ -36,6 +36,9 @@ jobs:
         if: ${{ matrix.os_name == 'Linux' }}
         shell: bash
         run: |
+          wget -O /usr/share/keyrings/llvm-snapshot.gpg.key https://apt.llvm.org/llvm-snapshot.gpg.key
+          echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.key] http://apt.llvm.org/noble/ llvm-toolchain-noble-20 main" | sudo tee -a /etc/apt/sources.list.d/llvm.list
+
           sudo apt-get update
           sudo apt-get install -y clang++-20 python3-venv
           sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-20 100

.github/workflows/libjs-test262.yml

@@ -50,8 +50,8 @@ jobs:
 
       - name: Install dependencies
         run: |
-          wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-          sudo add-apt-repository 'deb http://apt.llvm.org/noble/ llvm-toolchain-noble-20 main'
+          wget -O /usr/share/keyrings/llvm-snapshot.gpg.key https://apt.llvm.org/llvm-snapshot.gpg.key
+          echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.key] http://apt.llvm.org/noble/ llvm-toolchain-noble-20 main" | sudo tee -a /etc/apt/sources.list.d/llvm.list
 
           sudo apt-get update -y
           sudo apt-get install -y ninja-build unzip clang-20 clang++-20 jq wget curl zip tar autoconf autoconf-archive automake nasm pkg-config libgl1-mesa-dev rsync