CI: Don't install arm-none-eabi-gcc

This was probably never needed for liboscore in the first place.

.github/workflows/main.yml

@@ -83,7 +83,7 @@ jobs:
           git config --global user.name "CI"
           cargo binstall --no-confirm --no-symlinks --force --no-discover-github-token laze
           echo "$HOME/.cargo/bin" >> $GITHUB_PATH
-          sudo apt-get install ninja-build gcc-arm-none-eabi
+          sudo apt-get install ninja-build
 
       - name: "Show installed versions"
         run: |
@@ -92,7 +92,6 @@ jobs:
           llvm-config --libs
           cargo version
           laze --version
-          arm-none-eabi-gcc --version
           clang --version
           set +x
           # Check which alternative versions are installed