try update-alternatives to use gcc-10

Author: lukewilliamboswell

.github/workflows/ci.yml

@@ -51,8 +51,9 @@ jobs:
       - name: Update GCC
         run: |
           sudo apt-get update
-          sudo apt remove gcc-9
-          sudo apt install gcc-10
+          sudo apt-get install -y gcc-10
+          sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-10 100
+          sudo update-alternatives --set gcc /usr/bin/gcc-10
           gcc --version
 
       - name: Run all tests