Install automake to get missing aclocal

Author: sverhoeven

.github/workflows/ci.yml

@@ -9,6 +9,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - name: Install automake
+      run: sudo apt-get install automake
     - name: Setup Ruby
       uses: ruby/[email protected]
       with: