chore(deps): bump fluxcd/flux2 from 0.38.3 to 0.39.0 (#6208)

Bumps [fluxcd/flux2](https://github.com/fluxcd/flux2) from 0.38.3 to 0.39.0.
- [Release notes](https://github.com/fluxcd/flux2/releases)
- [Changelog](https://github.com/fluxcd/flux2/blob/main/.goreleaser.yml)
- [Commits](a9f53b4f1a...978cc0c5b8)

---
updated-dependencies:
- dependency-name: fluxcd/flux2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/release.yaml

@@ -188,7 +188,7 @@ jobs:
       - name: Setup build env
         uses: ./.github/actions/setup-build-env
       - name: Setup Flux CLI
-        uses: fluxcd/flux2/action@a9f53b4f1aef910fab68f790f7bf5b49c9a1677c # v0.38.3
+        uses: fluxcd/flux2/action@978cc0c5b8b85a976edd7e457a09b0f4d1255390 # v0.39.0
         with:
           version: 0.35.0
       - name: Install Cosign