Show skip message in stderr

.buildkite/pipeline.trigger.integration.tests.sh

@@ -3,6 +3,9 @@
 # exit immediately on failure, or if an undefined variable is used
 set -eu
 
+echoerr() {
+    echo "$@" 1>&2
+}
 
 # begin the pipeline.yml file
 echo "steps:"
@@ -74,7 +77,7 @@ pushd test/packages/parallel > /dev/null
 for package in $(find . -maxdepth 1 -mindepth 1 -type d) ; do
     package_name=$(basename "${package}")
     if [[ "$package_name" == "aws" || "$package_name" == "aws_logs" || "$package_name" == "gcp" ]] ; then
-        echo "Skip temporarily ${package_name}"
+        echoerr "Skip temporarily ${package_name}"
         continue
     fi
     echo "      - label: \":go: Running integration test: ${package_name}\""