Merge branch 'docs-add-include-as-reserved-job-name' into 'master'

Add include to the list of unusable job names

See merge request gitlab-org/gitlab!21221

doc/ci/yaml/README.md

@@ -75,6 +75,7 @@ cannot be used as job names**:
 - `after_script`
 - `variables`
 - `cache`
+- `include`
 
 ### Using reserved keywords