use text variable as variable in puts-warn

bin/steps/python

@@ -7,8 +7,6 @@ PYTHON_VERSION=$(cat runtime.txt)
 # The location of the pre-compiled python binary.
 VENDORED_PYTHON="${VENDOR_URL}/runtimes/$PYTHON_VERSION.tar.gz"
 
-# "https://lang-python.s3.amazonaws.com/heroku-16/runtimes/python-3.6.6.tar.gz"
-
 SECURITY_UPDATE="Python has released a security update! Please consider upgrading to "
 
 # check if runtime exists
@@ -16,28 +14,28 @@ if curl --output /dev/null --silent --head --fail $VENDORED_PYTHON; then
   if [[ $PYTHON_VERSION == $PY37* ]]; then
     # do things to alert the user of security release available
     if [ $PYTHON_VERSION != $LATEST_37 ]; then
-      puts-warn SECURITY_UPDATE $LATEST_37
+      puts-warn $SECURITY_UPDATE $LATEST_37
       echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
     fi
   fi
   if [[ $PYTHON_VERSION == $PY36* ]]; then
     # security update note
     if [ $PYTHON_VERSION != $LATEST_36 ]; then
-      puts-warn SECURITY_UPDATE $LATEST_36
+      puts-warn $SECURITY_UPDATE $LATEST_36
       echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
     fi
   fi
   if [[ $PYTHON_VERSION == $PY35* ]]; then
     # security update note
     if [ $PYTHON_VERSION != $LATEST_35 ]; then
-      puts-warn SECURITY_UPDATE $LATEST_35
+      puts-warn $SECURITY_UPDATE $LATEST_35
       echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
     fi
   fi
   if [[ $PYTHON_VERSION == $PY27* ]]; then
     # security update note
     if [ $PYTHON_VERSION != $LATEST_27 ]; then
-      puts-warn SECURITY_UPDATE $LATEST_27
+      puts-warn $SECURITY_UPDATE $LATEST_27
       echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
     fi
   fi