fix typo of filename kustomization.yaml (#6974)

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

Author: trent-s

website/content/en/docs/upgrading-sdk-version/v1.40.0.md

@@ -278,7 +278,7 @@ _See [#6928](https://github.com/operator-framework/operator-sdk/pull/6928) for m
 
 **Changes required under the hood `config/prometheus/`**
 
-- 1. Update the `config/prometheus/kutomization.yaml` add at the bottom:
+- 1. Update the `config/prometheus/kustomization.yaml` add at the bottom:
 
 ```yaml
       # [PROMETHEUS-WITH-CERTS] The following patch configures the ServiceMonitor in ../prometheus