The action doesn't seem to work, adding some trace print to make

sure the environment variables follow documentation.

Author: Martin Hansson

.github/workflows/ci.yml

@@ -59,6 +59,9 @@ jobs:
           apt-get update
           apt-get install -y git
           git config --global --add safe.directory '*'
+          echo GITHUB_SERVER_URL '${GITHUB_SERVER_URL}'
+          echo GITHUB_REPOSITORY '${GITHUB_REPOSITORY}'
+          echo GITHUB_REPOSITORY_OWNER '${GITHUB_REPOSITORY_OWNER}'
           git clone "${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}" .
           git checkout $GITHUB_HEAD_REF