ci: bump crazy-max/ghaction-import-gpg from 5 to 6

Bumps [crazy-max/ghaction-import-gpg](https://github.com/crazy-max/ghaction-import-gpg) from 5 to 6.
- [Release notes](https://github.com/crazy-max/ghaction-import-gpg/releases)
- [Commits](crazy-max/ghaction-import-gpg@v5...v6)

---
updated-dependencies:
- dependency-name: crazy-max/ghaction-import-gpg
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/cd.yml

@@ -42,7 +42,7 @@ jobs:
       - name: Import GPG key
         if: startsWith(github.ref, 'refs/tags/v')
         id: import_gpg
-        uses: crazy-max/ghaction-import-gpg@v5
+        uses: crazy-max/ghaction-import-gpg@v6
         with:
           gpg_private_key: ${{ secrets.GPG_PRIVATE_KEY }}
           passphrase: ${{ secrets.PASSPHRASE }}