doc: Update env variable mentioned in Authoring Guide (GoogleCloudPlatform#7406)

Mariatta · web-flow · commit 979dc78bc367 · 2022-01-28T11:29:16.000-05:00
The correct value to be changed in `testing/test-env.sh` is `GOOGLE_CLOUD_PROJECT` instead of `GCLOUD_PROJECT`. Source: https://github.com/GoogleCloudPlatform/python-docs-samples/blob/1d6736bd49778b2440e348890ec444d785c4fb60/testing/test-env.tmpl.sh#L16
diff --git a/AUTHORING_GUIDE.md b/AUTHORING_GUIDE.md
@@ -640,7 +640,7 @@ We suggest that you copy this file as follows:
 
 ```sh
 $ cp testing/test-env.tmpl.sh testing/test-env.sh
-$ editor testing/test-env.sh  # change the value of `GCLOUD_PROJECT`.
+$ editor testing/test-env.sh  # change the value of `GOOGLE_CLOUD_PROJECT`.
 ```
 
 You can easily `source` this file for exporting the environment variables.
