Fix misnamed GitLab file

Correct extension from 'yaml' to 'yml'.

doc/user/infrastructure/mr_integration.md

@@ -72,10 +72,10 @@ To manually configure a GitLab Terraform Report artifact requires the following
          terraform: $PLAN_JSON
    ```
 
-   For a full example using the pre-built image, see [Example `.gitlab-ci.yaml`
-   file](#example-gitlab-ciyaml-file).
+   For a full example using the pre-built image, see [Example `.gitlab-ci.yml`
+   file](#example-gitlab-ciyml-file).
 
-   For an example displaying multiple reports, see [`.gitlab-ci.yaml` multiple reports file](#multiple-terraform-plan-reports).
+   For an example displaying multiple reports, see [`.gitlab-ci.yml` multiple reports file](#multiple-terraform-plan-reports).
 
 1. Running the pipeline displays the widget in the merge request, like this:
 
@@ -86,7 +86,7 @@ To manually configure a GitLab Terraform Report artifact requires the following
 
    ![Terraform plan logs](img/terraform_plan_log_v13_0.png)
 
-### Example `.gitlab-ci.yaml` file
+### Example `.gitlab-ci.yml` file
 
 ```yaml
 default:

doc/user/project/releases/index.md

@@ -200,7 +200,7 @@ If the job that's executing is within a freeze period, GitLab CI/CD creates an e
 variable named `$CI_DEPLOY_FREEZE`.
 
 To prevent the deployment job from executing, create a `rules` entry in your
-`gitlab-ci.yaml`, for example:
+`gitlab-ci.yml`, for example:
 
 ```yaml
 deploy_to_production: