In nodejs cloudendpoints lab prepare_environment.sh, you deploy nodejs14, which is no longer supported. If you update to the below, it will automatically choose the oldest supported version.
NODEJS_VERSION=$(gcloud functions runtimes list --region us-central1 --filter nodejs | head -n2 | awk ' { print $1 } ')
gcloud functions deploy process-feedback --gen2 --runtime $NODEJS_VERSION --region us-central1 --trigger-topic feedback --source ./function --stage-bucket $GCLOUD_BUCKET --entry-point subscribe --allow-unauthenticated
Also, google-p12-pem is no longer maintained, but I don't know which dependency is using it.