Indicated the Artifacts:paths can accept CI expansion

```yaml
job:
  variables:
    EXAMPLE: filename
  ...
  artifacts:
    paths: 
      - ${EXAMPLE}.yaml
```

doc/ci/variables/where_variables_can_be_used.md

@@ -27,6 +27,7 @@ There are two places defined variables can be used. On the:
 |:----------------------------------------------------------------------|:-----------------|:-----------------------|:------------|
 | [`after_script`](../yaml/index.md#after_script)                       | yes              | Script execution shell | The variable expansion is made by the [execution shell environment](#execution-shell-environment). |
 | [`artifacts:name`](../yaml/index.md#artifactsname)                    | yes              | Runner                 | The variable expansion is made by GitLab Runner's shell environment. |
+| [`artifacts:paths`](../yaml/index.md#artifactspaths)                  | yes              | Runner                 | The variable expansion is made by GitLab Runner's shell environment. |
 | [`before_script`](../yaml/index.md#before_script)                     | yes              | Script execution shell | The variable expansion is made by the [execution shell environment](#execution-shell-environment) |
 | [`cache:key`](../yaml/index.md#cachekey)                              | yes              | Runner                 | The variable expansion is made by GitLab Runner's [internal variable expansion mechanism](#gitlab-runner-internal-variable-expansion-mechanism). |
 | [`cache:policy`](../yaml/index.md#cachepolicy)                        | yes              | Runner                 | The variable expansion is made by GitLab Runner's [internal variable expansion mechanism](#gitlab-runner-internal-variable-expansion-mechanism). |