changing how it references link yet again

Author: B00885424

.github/workflows/ci.yml

@@ -19,5 +19,5 @@
       uses: puppetlabs/cat-github-actions/.github/workflows/module_acceptance.yml@main
       with:
         flags: --provision-service
-        APT_SOURCES: ${{'https://artifactory.delivery.puppetlabs.net:443/artifactory/internal_nightly__local/apt' }}
+        APT_SOURCES: ${{ github.event.inputs.APT_SOURCES || 'https://artifactory.delivery.puppetlabs.net:443/artifactory/internal_nightly__local/apt' }}
       secrets: inherit