chore: adding @dgershman (#2506)

## Description

Adding @dgershman (from @radiusmethod) as a CODEOWNERS.

## Related Issue

N/A

## Checklist before merging

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

CODEOWNERS

@@ -1,4 +1,4 @@
-* @defenseunicorns/zarf
+* @defenseunicorns/zarf @dgershman
 
 /CODEOWNERS @jeff-mccoy @austenbryan
 /cosign.pub @jeff-mccoy @austenbryan