Fix CI issue with grub-efi

See this thread actions/runner-images#7192 (comment)

.github/workflows/ci-main.yml

@@ -21,6 +21,7 @@ jobs:
     steps:
       - name: Freeing up more disk space
         run: |
+          echo 'APT::Get::Always-Include-Phased-Updates "false";' | sudo tee /etc/apt/apt.conf.d/99-phased-updates
           sudo rm -rf /usr/local/lib/android # will release about 10 GB if you don't need Android
           sudo rm -rf /usr/share/dotnet # will release about 20GB if you don't need .NET
       - uses: actions/checkout@v2