docs: fix casing on code of conduct badge (#2466)

## Description
Fix from last PR

## Related Issue

Fixes #
<!-- or -->
Relates to #

## Checklist before merging

- [ ] Test, docs, adr added or updated as needed
- [ ] [Contributor Guide
Steps](https://github.com/defenseunicorns/zarf/blob/main/.github/CONTRIBUTING.md#developer-workflow)
followed

README.md

@@ -12,7 +12,7 @@
 [![Zarf Documentation](https://img.shields.io/badge/docs-docs.zarf.dev-775ba1)](https://docs.zarf.dev/)
 [![Zarf Slack Channel](https://img.shields.io/badge/k8s%20slack-zarf-40a3dd)](https://kubernetes.slack.com/archives/C03B6BJAUJ3)
 [![Community Meetups](https://img.shields.io/badge/community-meetups-22aebb)](https://github.com/defenseunicorns/zarf/issues/2202)
-[![Contributor Covenant](https://img.shields.io/badge/Contributor%20Covenant-2.1-4baaaa.svg)](code_of_conduct.md)
+[![Contributor Covenant](https://img.shields.io/badge/Contributor%20Covenant-2.1-4baaaa.svg)](CODE_OF_CONDUCT.md)
 
 Zarf eliminates the [complexity of air gap software delivery](https://www.itopstimes.com/contain/air-gap-kubernetes-considerations-for-running-cloud-native-applications-without-the-cloud/) for Kubernetes clusters and cloud-native workloads using a declarative packaging strategy to support DevSecOps in offline and semi-connected environments.