update drone signature (grafana#10087)

**What this PR does / why we need it**:

**Which issue(s) this PR fixes**:
Fixes #<issue number>

**Special notes for your reviewer**:

**Checklist**
- [ ] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [ ] Documentation added
- [ ] Tests updated
- [ ] `CHANGELOG.md` updated
- [ ] If the change is worth mentioning in the release notes, add
`add-to-release-notes` label
- [ ] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/setup/upgrade/_index.md`
- [ ] For Helm chart changes bump the Helm chart version in
`production/helm/loki/Chart.yaml` and update
`production/helm/loki/CHANGELOG.md` and
`production/helm/loki/README.md`. [Example
PR](grafana@d10549e)

Signed-off-by: Edward Welch <edward.welch@grafana.com>

.drone/drone.yml

@@ -1910,6 +1910,6 @@ kind: secret
 name: gpg_private_key
 ---
 kind: signature
-hmac: a1839eb5d43146ccc7793a2bb103396a4ca370582fed4736c24c4c9b7c4d55e3
+hmac: d87780f1737fccb4d0409e34fc97ee07e1bd3c45c9b25fae517e7dbd21fc7a5f
 
 ...