fix small typo in filename (#6886)

Signed-off-by: Scott Trent <[email protected]>

website/content/en/docs/upgrading-sdk-version/v1.38.0.md

@@ -214,7 +214,7 @@ if these migrations become difficult to follow, it might be beneficial to scaffo
     + - --health-probe-bind-address=:8081
     ```
 
-13) [go/v4, helm/v1, ansible/v1] Update your `/config/prometheus/monitor/yaml` file with the below changes:
+13) [go/v4, helm/v1, ansible/v1] Update your `/config/prometheus/monitor.yaml` file with the below changes:
     ```diff
          - path: /metrics
     -      port: https