release.yml: use krystianduma as NuGet/login user

The NuGet trusted publishing token exchange requires the username of the
policy creator (the nuget.org login that created the policy), not the
policy-owner organization. krystianduma created the policy under the
KDuma organization.

Author: claude

.github/workflows/release.yml

@@ -185,7 +185,7 @@ jobs:
         if: needs.resolve.outputs.dry_run != 'true'
         uses: NuGet/login@v1
         with:
-          user: kduma
+          user: krystianduma
       - name: dotnet nuget push
         if: needs.resolve.outputs.dry_run != 'true'
         run: |