Update docs environment:action:stop GIT_STRATEGY

Notes that `GIT_STRATEGY` should be set to `none` so that the
job doesn't fail when triggered automatically when the branch
is deleted.

doc/ci/yaml/README.md

@@ -973,6 +973,8 @@ review_app:
 
 stop_review_app:
   stage: deploy
+  variables:
+    GIT_STRATEGY: none  
   script: make delete-app
   when: manual
   environment:
@@ -987,6 +989,10 @@ Once the `review_app` job is successfully finished, it will trigger the
 set it up to `manual` so it will need a [manual action](#whenmanual) via
 GitLab's web interface in order to run.
 
+Also in the example, `GIT_STRATEGY` is set to `none` so that GitLab Runner won’t
+try to check out the code after the branch is deleted when the `stop_review_app`
+job is [automatically triggered](../environments.md#automatically-stopping-an-environment).
+
 The `stop_review_app` job is **required** to have the following keywords defined:
 
 - `when` - [reference](#when)