Update test-env.tmpl.sh (GoogleCloudPlatform#6928)

* Update test-env.tmpl.sh

Adds variable used for samples that require testing against a Composer v2 environment

* Update test-env.tmpl.sh

Author: leahecole

testing/test-env.tmpl.sh

@@ -26,6 +26,9 @@ export BIGTABLE_INSTANCE=
 export SPANNER_INSTANCE=
 export COMPOSER_LOCATION=us-central1
 export COMPOSER_ENVIRONMENT=
+export COMPOSER2_ENVIRONMENT=
+# Webserver for COMPOSER2_ENVIRONMENT
+export COMPOSER2_WEB_SERVER_URL=
 export CLOUD_KMS_KEY=
 
 export MYSQL_INSTANCE=
@@ -105,4 +108,4 @@ export CONNECTOR=
 
 # Dialogflow examples.
 export SMART_REPLY_MODEL=
-export SMART_REPLY_ALLOWLIST=
+export SMART_REPLY_ALLOWLIST=