define the SITEENV to the multidev name

.github/workflows/sage-test.yml

@@ -109,6 +109,7 @@ jobs:
           export SAGENAME=sage-test
           export SITENAME=wpcm-sage-install-tests
           export CI=1
+          export SITEENV=$multidev_name
           cd ~/pantheon-local-copies/$SITENAME
           composer install-sage || exit_code=$?
           if [[ -n "${exit_code}" ]]; then